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(ISSN 0015-4040)
FLORIDA ENTOMOLOGIST
(An International Journal for the Americas)
Volume 68, No. 2 June, 1985
TABLE OF CONTENTS
68th Annual Meeting Announcement -..-.... ...............- ..~..... ... .. i
10th Congress of Brazilian Entomology Announcement .- ... ....--. i
Student Scholarship Grants .-...... -...............----- .... ii
KIDD, K. A., C. S. APPERSON, AND L. A. NELSON-Recruitment of the
Red Imported Fire Ant, Solenopsis invicta, to Soybean Oil Baits 253
TRAGER, J. C. AND C. JOHNSON-A Slave-making Ant in Florida; Polyer-
gus lucidus With Observations on the Natural History of its
Host Formica archboldi (Hymenoptera) Formicidae .. .. 261
SCHUSTER, J. C. AND L. B. SCHUSTER-Social Behavior in Passalid
Beetles (Coleoptera: Passalidae): Cooperative Brood Care -..-- 266
SIVINSKI, J., AND J. C. WEBB-Sound Production and Reception in the
Caribfly, Anastrepha suspense (Diptera: Tephritidae) ....- 273
GONZALEZ, J. M., R. W. MATTHEWS, AND J. R. MATTHEWS-A Sex Phero-
mone in Males of Melittobia australica and M. femorata (Hy-
menoptera: Eulophidae) --....- ....-----.. .....--..-........... 279
SZLENDAK, E., J. BOCZEK, W. BRUCE, AND R. DAVIS-Effect of Gamma-
radiated Males on Egg Production in Acarus siro -...- - 286
CARPENTER, J. E., J. R. YOUNG, AND A. N. SPARKS-Fall Armyworm
(Lepidoptera: Noctuidae): Field Survival of F1 Larvae from
Partially Sterile Parents ---- --- --- ---.- --.-..-...... 290
CHANG, N. T., B. R. WISEMAN, AND R. E. LYNCH-Fall Armyworm
(Lepidoptera: Noctuidae) Orientation and Preference for Se-
lected Grasses ------.~-....... ---- .....-. ..------....______ 296
ALI, A., AND R. C. FOWLER-A Natural Decline of Pestiferous Chironi-
dae (Diptera) Populations from 1979 to 1984 in an Urban Area
of Central Florida .............................- ---......-----.----- ....... 304
GIST, G. L., AND C. D. PLESS-Comparative Toxicities of Synthetic
Pyrethroids to the Fall Armyworm, Spodoptera frugiperda ---. 312
GIST, G. L., AND C. D. PLESS-Synergistic Activity of Pyperonyl Bu-
toxide with Nine Synthetic Pyrethiods Against the Fall Army-
worm, Spodoptera frugiperda ....---..- -............ .... 316
HENRY, T. J.-Caulotops distant (Miridae: Heteroptera), A Potential
Yucca Pest Newly Discovered in the United States 320
Continued on Back Cover
Published by The Florida Entomological Society
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OFFICERS FOR 1984-85
President ................-------- ....-- ... ...---.... -----......................- M. L. W right, Jr.
President-Elect ---------- ...---........ ......... ... D. H. Habeck
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Secretary .-......... -- ---------..........--.................. D. F. Williams
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This issue mailed June 10, 1985
68th ANNUAL MEETING-FLORIDA ENTOMOLOGICAL SOCIETY
1. DATE AND LOCALE: August 5-8, 1985; Ocho Rios Sheraton Hotel;
Ocho Rios, Jamaica, West Indies.
2. OFFICIAL TRAVEL AGENCY: EMMER TRAVEL, INC., 2801 S.W.
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10TH CONGRESS OF BRAZILIAN ENTOMOLOGY
The 9th Congress of Brazilian Entomology was held in Londrina, Parana
in July 1984 with more than 600 participants. It was a very special meeting
with round tables, feature speakers, panels, hundreds of research papers
covering all aspects of Entomology. There was great interest in the competi-
tion of papers presented by graduate students.
The newly elected President is Jocelia Grazia, researcher from the Federal
University of Rio Grande do Sul, Porto Alegre; Vice-President is Euripedes
B. deMenezes; both well known in international circles.
The next Congress will be held in Rio de Janeiro 26-31 of January in
1986 in the Hotel Gloria. Plan to attend. For more information on member-
ship and future meetings, write to:
Sociedade Entomologicaide Brasil
A/C Ruth H. Mocellin
Depto. de Zoologia-UFRGS
Av. Paulo Gama, S/N
90.000 Porto Algre-RS
BRASIL
STUDENT SCHOLARSHIP GRANTS
The Florida Entomological Society will award three $500.00 scholarship
grants to students majoring in entomology. The criteria for selecting the
awardees are:
1. The student must be a member of the Florida Entomological Society.
2. The quality of scholarship reflected in students transcript.
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Application packages must be mailed to D. L. Shankland, Deperatment of
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on or before July 1, 1985.
Kidd et al: Fire Ant Recruitment
RECRUITMENT OF THE RED IMPORTED FIRE ANT,
SOLENOPSIS INVICTA, TO SOYBEAN OIL BAITS
KATHLEEN A. KIDD AND CHARLES S. APPERSON
Department of Entomology
Box 7613
North Carolina State University
Raleigh, NC 27695-7613
LARRY A. NELSON
Department of Statistics
Box 8203
North Carolina State University
Raleigh, NC 27695-8203
ABSTRACT
A field investigation was conducted to compare the diel periodicity and
rates of recruitment of the red imported fire ant, Solenopsis invicta Buren, to
soybean oil presented in two forms. Bimodal patterns of recruitment were
usually observed to corn cob particulates saturated with oil but not to cotton
wicks saturated with oil. Recruitment to both rates was usually higher at
night but not always significantly (P 0.05) different from rates observed
during the day. Significantly (P 0.05) higher rates of recruitment oc-
curred to the particulate oil bait relative to the liquid oil bait at most times
studied. The size of ants recruited to the two baits varied significantly
(P n 0.05); however, no consistent or explainable pattern in the size of
ants recruited over each 24-hour period was observed for either bait. Ants
of the media worker subcaste were generally recruited at significantly
(P 0.05) greater rates to both baits relative to minor and major workers.
Standard multiple regression analyses revealed that changes in air and
soil temperatures had a significant (P = 0.05) impact on recruitment; how-
ever, changes in air and soil moisture did not appear to influence rates of
recruitment to the baits.
RESUME
Se condujo una investigation en el campo para comparar la periocidad
"diel" y los grades de obtener aceite de soya presentado en dos formas por
la hormiga roja importada, Solenopsis invicta Buren. Se observ6 un patr6n
bi-modelo en la obtenci6n de particular de mazorca de maiz saturadas en
aceite pero no en mechas de algod6n saturadas en aceite. La obtenci6n a
ambos niveles usualmente fue mas alta de noche, pero no siempre sig-
nificativamente diferente (P 0.05) de los grades observados durante el dia.
La mayoria de las veces que se estudi6, se obtuvo significantemente (P
, 0.05) grades mAs alto de obtenci6n ocurrido con trampas de cebo con
particular de aceite relative a cebos de aceite liquid. El tamafio de las
hormigas obtenidas en las dos trampas vari6 significantemente (P 0.05),
sin embargo no se observe un patron explicable o consistent en el tamaflo
de las hormigas obtenidas durante un period de 24 horas en ninguna de
las trampas. Hormigas trabajadoras de la sub-casta media fueron general-
mente obtenidas en grades significantemente (P 0.05) mAs altos relative
a trabajadoras menores y mayores hacia ambos cebos. La norma del analisis
de regresi6n multiple revel6 que cambios de temperature en el aire y en ]a
tierra tuvieron un impact significant (P 0.05) en lo obtenci6n, sin em-
253
254 Florida Entomologist 68 (2) June, 1985
bargo, cambio en la humedad aire y de la tierra aparentemente no influyeron
los grades de obtenci6n de las trampas.
INTRODUCTION
The red imported fire ant, Solenopsis invicta Buren, has spread through-
out a large portion of the Southeast after being introduced into the United
States from South America (Lofgren et al. 1975). S. invicta is a highly
territorial species (Wilson et al. 1971) that is characterized by the large
size of its colonies (Lofgren et al. 1975) and the mass recruitment of work-
er ants to food sources (Wilson 1962). Efforts to control S. invicta popula-
tions have traditionally involved the use of soybean oil-insecticide mixtures
impregnated on corn cob particles (Lofgren et al. 1975). Foraging workers
retrieve particles that have been broadcast over infested areas or spread
around the perimeter of S. invicta colonies. Since some currently used toxic
baits are rapidly degraded (Apperson et al. 1984, Vander Meer et al. 1982),
knowledge of recruitment activities would help to improve the timing of
bait applications and thereby improve the efficiency of control programs.
The objectives of our investigation were: (1) to compare recruitment
over a 24-hour period to two forms of soybean oil baits; and (2) to deter-
mine the impact of some meteorological and edaphic factors on S. invicta
recruitment activities.
METHODS AND MATERIALS
Experiments were conducted in a 6.1-ha field near Bolivia, Brunswick
County, North Carolina, between May and July 1982, prior to the planting
of soybeans (Glycine max (L.) Merr.). The field had been disked in the
fall of 1981, and some weeds, primarily sicklepod (Cassia obtusifolia L.),
Pennsylvania smartweed (Polygonum pensylvanicum L.), and morning glory
(Ipomea spp.) were found across the field.
BAITS
Once-refined soybean oil was used as bait. Soybean oil was chosen as:
a stationary, concentrated food source because it is readily accepted by
S. invicta (Hays and Arant 1960, Lofgren et al. 1964) and is easily dis-
tributed on a particulate carrier (Lofgren et al. 1973). Once-refined soy-
bean oil was presented in two forms: on a corncob grit carrier; and in one
dram vials fitted with cotton wicks. The particulate bait was placed in a
pile on a flat plastic dish 15 cm in diameter. The liquid bait was contained
in 12 vials arranged in a circle and inserted horizontally to ca. one-half
their length into holes punched near the bottom of a plastic container. This
container was pushed down into the soil so that the wicks contacted the
soil surface. These two bait stations were left in place throughout each 24-
hour observation period.
EXPERIMENTAL AREA AND PLACEMENT OF BAITS
Sampling was carried out near two S. invicta mounds which were located
adjacent to pine woods at the periphery of the field. The mounds were of
Kidd et al: Fire Ant Recruitment 255
similar size (ca. 0.6 x 0.4 x 0.3 m high) and were ca. 115 m apart. A par-
ticulate oil bait was placed ca. 6 m away from one mound and a liquid
oil bait was placed ca. 6 m from the other mound. On each successive samp-
ling date, the bait stations were switched to the opposite mounds to preclude
effects of hunger state, food preference or colony size upon recruitment rates.
The liquid and particulate baits were placed in the field one hour before
observations were initiated to allow ants to locate the baits and establish
recruitment trails.
OBSERVATIONS
At the recruitment trail established to each bait station, a string was
tied across the trail between two stakes about 1 m from each bait. Ants
moving past this point, traveling toward the bait, were counted. Because
the ant trail was usually disrupted by the approach of an observer, it was
necessary to wait several minutes until regular traffic flow resumed before
observations were made. Once the flow resumed, all ants passing under
the string on their way to the bait were counted for 2 minutes. Counts were
made every 4 hours, with a total of 7 counts made for each 24-hour period.
A headlamp was used to make observations at night. A diel sampling was
carried out on 5 dates. Observations for the first sampling date (May 27)
were initiated at 0900 hrs, the second (June 2) at 1400 hrs, and third (June
15), fourth (June 28), and fifth (July 2) at 1600 hrs.
Some of the ants running on the recruitment trails were collected' with
an aspirator during each observation. These ants were brought back to the
laboratory and their head capsule widths were measured to determine if
there were any changes in the size of workers recruited to the baits over
time. Voucher specimens of fire ants have been deposited in the Entomology
Museum of North Carolina State University.
ABIOTIC AND EDAPHIC PARAMETERS
Measurements of air and soil temperature, relative humidity, and soil
moisture for correlation with fire ant recruitment activities were taken
following each observation period. Temperatures were measured with an
Extech Model 1200 digital thermometer, and all readings were taken
close to the recruitment trail without disturbing the ants. Air temperature
was measured ca. 3 cm above the soil surface and soil temperature was
measured after pushing the probe just under the surface. A Bacharach
sling psychrometer was used to measure relative humidity. For moisture
determinations, shallow soil samples were taken with a Hoffer sampler. The
samples were weighed in the field immediately after collection to the near-
est 0.1 g and then brought back to the laboratory and dried in an oven to a
constant weight. Values for soil moisture were calculated on a percent dry
weight basis. Temperature, soil moisture and relative humidity data were
collected at each bait station.
STATISTICAL ANALYSES
A contingency table was constructed for the numbers of ants counted
running toward the 2 baits at the 7 time intervals on each and over all
sampling dates. Chi-square tests were carried out to determine if the re-
Florida Entomologist 68 (2)
June, 1985
cruitment rates to the baits varied independently and also to test the hypo-
thesis of equal recruitment for the two baits at a given date. The partition-
ing of the chi-square for bait x date x time was accomplished by the
FUNCAT procedure of the Statistical Analysis System (Helwig and
Council 1979). Standard multiple regression procedures were used to de-
termine effects of the temperature and moisture variables on recruitment
rates to the baits.
Measurements of S. invicta head capsule width were grouped according
to the worker subcaste classification of Wilson (1978). Chi-square tests
were carried out to determine if the numbers of ants of each subcaste re-
cruited to the two baits varied independently. Unless otherwise indicated, all
statistical analyses were performed at the P 0.05 level of significance.
RESULTS AND DISCUSSION
PERIODICITY OF RECRUITMENT
Recruitment to the particulate bait exhibited a bimodal pattern on 4
of the 5 sampling dates (Fig. 1). When trials were initiated in the late
afternoon, recruitment activity was observed to peak at night and again
the following day. The opposite situation occurred when the trials were
started in the morning or early afternoon. A bimodal pattern of recruit-
ment to the liquid bait generally was not found. Movement of ants along the
A
I /
1^
f NIGHT -
F NIGHT -
v NIGHT
May 27 (---)
June 2 (--
June 15 (.........)
June 28 (---)
July 2 (-**)
1200 1600 2000 2400 0400 0800 1200 1600 2000 2400 0400 E8 1200
Fig. 1. Diel recruitment of S. invicta to particulate (A) and liquid (B)
soybean oil baits.
256
Kidd et al: Fire Ant Recruitment 257
recruitment trails decreased at the end of the 24-hour observation periods,
sometimes ceasing altogether regardless of when the trials were initiated.
Recruitment to both baits was usually higher at night but not always sig-
nificantly different from rates observed during the day.
IATES OF RECRUITMENT TO LIQUID AND PARTICULITE OIL BAITS
Movement of S. invicta to the liquid bait was slower than to the par-
ticulate bait, and the differences were highly significant (P 0.01) (Table
1). The hypothesis of equal recruitment between the two baits was rejected
for all but one of the dates studied (Table 2). There are several plausible
explanations for observed differences in recruitment to the two baits. A
time factor may be involved. Ants had to stay at the vials to drink from
the wicks which required more time than transporting an individual bait
particle to the nest. Taylor (1978) recognized time spent drinking as an
important variable in his model of recruitment rates of Solenopsis geminata
(F.). The surface area of a food source is another important determinant
of recruitment; Wilson (1962) and Taylor (1977) showed that the number
of worker ants at a food mass is related to the surface area of the food
mass. In our investigation, the particulate bait provided a larger surface
area relative to the liquid bait; however, differences in the surface area
TABLE 1. COMPARISON OF THE RATES OF RECRUITMENT OF S. invicta WORKER
ANTS TO PARTICULATE AND LIQUID SOYBEAN OIL BAITS.
Prob.>
Date Chi-square" chi-square
May 27 15.63 0.008
June 2 24.64 0.0001
June 15 104.18 0.0001
June 28 39.84 0.0001
July 2 32.22 0.0001
Over all dates 97.36 0.0001
"Each chi-square value reported is from a 7 X 2 (Time of Day) X (Bait) contingency
table and is based on 6 degrees of freedom.
TABLE 2. COMPARISON OF TOTAL NUMBERS OF S. invicta WORKERS RECRUITED
TO PARTICULATE AND LIQUID SOYBEAN OIL BAITS.
Particulate Liquid Prob. >
Date bait bait Chi-square- chi-square
May 27 280 188 18.08 <0.005
June 2 591 114 269.60 <0.005
June 15 159 143 0.84 >0.10
June 28 315 186 33.22 <0.005
July 2 173 119 9.99 <0.005
Over all dates 1518 750 260.06 <0.005
"The chi-squares (df = 1) test the null hypothesis of equal recruitment between the
two baits. Significance of chi-square implies unequal recruitment for the two baits.
258 Florida Entomologist 68 (2) June, 1985
of the baits does not appear to be an important factor. Workers crowded
around individual wicks at the liquid bait, but all of the wicks were never
fully occupied by ants. Other factors known to affect recruitment, such as
colony size and size-age composition of workers (Sorensen et al. 1981),
hunger state (Howard and Tschinkel 1982) and food preferences (Glunn
et al. 1981), should have been of no consequence since the two types of soy-
bean oil baits were alternated between the S. invicta colonies used. Quality
of food could also influence the number of workers recruited to a food
source. Hangartner (1969) and Taylor (1977) found S. geminata to recruit
at greater rates when the concentration of sucrose solutions was increased.
Presumably, in our experiment, oil in liquid form would provide a more
concentrated, accessible food source (of higher quality) that could be easily
spread through the colony through trophallaxis. However, after a more
careful examination, the resource values of a worker-load of food (Carroll
and Janzen 1973) for the particulate oil bait appear to be greater. We
calculate that bait particles contained ca. 30 pg of oil since each particle
weighs an average of 0.2 mg and can absorb 15% of its weight in oil
(Lofgren et al. 1973). Because only 50% of the oil can be extracted from
the particulate bait (Banks et al. 1973), each worker-load of food is
equivalent to ca. 15 Ag of oil. Sorensen et al. (1981) determined that on the
average each S. invicta forager ingests 6.57 /g of oil from liquid baits. The
two values are sufficiently different to suggest that S. invicta may recruit at
higher rates to the particulate bait because each particle contains more
oil than a worker can consume. Additionally, the storage properties of the
two kinds of bait are quite dissimilar. Particulate bait could be easily stored
inside the nest and the oil consumed as needed; however, liquid bait would
have to be fed immediately to nest mates or retained (in a replete caste).
While there is evidence that both of these activities do occur in S. invicta
colonies, it would seem more likely that S. invicta colonies would have a
greater capacity in the short term to store particulate bait and for this
reason, they recruit to it at higher rates. Certainly more carefully con-
trolled experiments must be carried out to confirm this hypothesis.
RECRUITMENT OF SUBCASTES
Mirenda and Vinson (1981) and Wilson (1978) found that S. invicta
exhibits a weak polymorphism that is somewhat reflected in task specializa-
tion. Small (minor) workers were more likely to care for brood while large
(media and major) workers foraged and defended the nest. Wilson (1978)
correlated worker size with the size of particles transported. Small workers
carried particles of all sizes while larger workers tended to carry only the
larger particles. Mirenda and Vinson (1981) showed that media and major
foragers were more likely to retrieve solid insect prey than were minor
workers. Sorensen and Vinson (1981) reported differences in the size classes
or workers recruited to various kinds of food. Smaller numbers of workers
of all size classes were recruited to honey, but more media and major
workers were found when insects were presented as food. Howard and
Tschinkel (1981) found that on an ant-weight basis, foragers of all size
classes ingested similar quantities of oil. We found no evidence to suggest
that the form in which the oil was presented altered the size of ants re-
cruited. Our analysis of the numbers of ants of each S. invicta subcaste re-
cruited indicated that there were no significant differences between the
Kidd et al: Fire Ant Recruitment 259
two baits for the time periods within each sampling date (Table 3). No con-
sistent or biologically rational trend of increase or decrease in the proportion
of each subcaste recruited over each 24-hour sampling for each bait was
found when the data were examined. While the numbers of each subcaste
recruited to the 2 baits on each sampling date were found to vary inde-
pendently (Table 3), no consistent pattern of difference between the baits
was found. We did find that significantly greater numbers of media workers
were recruited to the baits relative to minor or major workers. In this re-
gard, our results are consistent with those reported by Mirenda and Vinson
(1981). They showed that media workers were more likely to forage rela-
tive to minor and major workers.
IMPACT OF ENVIRONMENTAL FACTORS ON RECRUITMENT
Attempts to determine the impact of environmental parameters on re-
cruitment yielded models that contained quadratic and interaction forms of
the time, temperature and moisture variables measured. Recruitment to the
baits did not show a strictly linear relationship with any of these parameters.
While air and soil temperatures did have a significant influence on recruit-
ment rates, the proportion of the total variation in recruitment explained
by these parameters was small (<25%). Air and soil moisture did not
appear to have a significant impact on recruitment to the baits.
Rhoades and Davis (1967) reported that the optimum range of air
temperature for S. invicta foraging activity is 210C to 290C with soil sur-
face temperatures below 350C. During our investigation, temperatures
rarely exceeded these optimum ranges. Air temperature declined below the
optimum range found by Rhoades and Davis once during our investigation,
but this did not have an adverse effect on recruitment. Because low tempera-
tures generally occurred at night, the observed recruitment patterns could
not be attributed solely to temperature. It is possible that high humidity
and darkness affected S. invicta recruitment activity. Recruitment to oil
baits continued throughout the night, usually showing a peak of activity
during the dark hours (Fig. 1). Recruitment to the liquid and particulate
baits was inhibited more by high temperatures at the end of the 24-hour
TABLE 3. ANALYSIS OF THE RECRUITMENT OF S. invicta WORKER SUBCASTES
TO PARTICULATE AND LIQUID SOYBEAN OIL BAITS.
Prob. >
Parameter dfa Chi-squareb chi-square
Intercept 2 4.13 0.127
Bait 2 0.50 0.779
Date 8 14.58 0.0677
Bait X date 8 57.70 0.0001
Bait X time 12 8.93 0.7091
Date X time 48 59.14 0.130
Bait X date X time 44c 48.60 0.293
aDegrees of freedom for intercept and Bait and Date main effects reflect the fact that
separate intercepts have been fitted for each bait.
bThe total chi-square for bait X date X time was partitioned by the FUNCAT pro-
cedure.
cDegrees of freedom reflect missing data.
260 Florida Entomologist 68 (2) June, 1985
period than at the beginning of the period regardless of when the trials
were initiated. This observation suggests that S. invicta will recruit to con-
centrated food sources during unfavorable environmental conditions until
the hunger state of the colony is satiated.
ENDNOTES
This is paper no. 8949 of the Journal Series of the N. C. Agric. Res. Serv.,
Raleigh.
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LOFGREN, C. S., W. A. BANKS AND B. M. GLANCEY. 1975. Biology and control
of imported fire ants. Ann. Rev. Entomol. 20: 1-30.
LOFGREN, C. S., F. J. BARTLETT AND C. E. STRINGER. 1973. Imported fire ant
toxic bait studies: evaluation of carriers for oil baits. J. Econ.
Entomol. 66: 62-66.
LOFGREN, C. S., F. J. BARTLETT AND C. E. STRINGER. 1964. The acceptability
of some fats and oils as food to imported fire ants. Ibid. 57: 601-602.
MIRENDA, J. T. AND S. B. VINSON. 1981. Division of labour and specification
of castes in the red imported fire ant Solenopsis invicta Buren. Anim.
Beh. 29: 410-420.
RHOADES, W. C. AND D. R. DAVIS. 1967. Effects of meteorological factors
on the biology and control of the imported fire ant. J. Econ. Entomol.
60: 554-558.
SORENSON, A. A., J. T. MIRENDA AND S. B. VINSON. 1981. Food exchange and
distribution by three functional worker groups of the imported fire
ant Solenopsis invicta Buren. Insectes Soc. 28: 383-394.
SORENSEN, A. A. AND S. B. VINSON. 1981. Quantitative food distribution
studies within laboratory colonies of the imported fire ant, Solenopsis
invicta Buren. Ibid. 28: 129-160.
TAYLOR, F. 1977. Foraging behavior of ants: experiments with two species
Kidd et al: Fire Ant Recruitment
of myrmecine ants. Behav. Ecol. Sociobiol. 2: 147-167.
TAYLOR, F. 1978. Foraging behavior of ants: theoretical considerations. J.
Theor. Biol. 71: 541-565.
VANDER MEER, R. K., D. F. WILLIAMS AND C. S. LOFGREN. 1982. Degrada-
tion of the toxicant AC217,300 in Amdro imported fire ant bait under
field conditions J. Agric. Food Chem. 30: 1045-1048.
WILSON, E. 0. 1962. Chemical communication among workers of the fire ant,
Solenopsis saevissima (Fr. Smith): 1. The organization of mass
foraging. Anim. Beh. 10: 134-147.
WILSON, E. 0. 1978. Division of labor in fire ants based on physical castes
(Hymenoptera: Formicidae: Solenopsis). J. Kansas Entomol. Soc. 51:
615-636.
WILSON, N. L., J. H. DILLIER AND G. P. MARKIN. 1971. Foraging territories
of imported fire ants. Ann. Entomol. Soc. America 64: 660-665.
A SLAVE-MAKING ANT IN FLORIDA: POLYERGUS
LUCIDUS WITH OBSERVATIONS ON THE NATURAL
HISTORY OF ITS HOST FORMICA ARCHBOLDI
(HYMENOPTERA: FORMICIDAE)
JAMES C. TRACER AND CLIFFORD JOHNSON
Department of Entomology and Nematology
and Department of Zoology
University of Florida
Gainesville, Florida 32611
ABSTRACT
The slave-making ant Polyergus lucidus is reported for the 1st time from
Florida. Formica archboldi is its host species, not previously known to be
parasitized in this way. The behavior of these 2 species is described and
compared to that of related forms from other regions.
RESUME
Se registra por primera vez la hormiga esclavista Polyergus lucidus de la
Florida. Formica archboldi es su hospedero, que no se conocia previamente
que era parasitado de esta forma. Se describe el comportamiento de las 2
species, y se compare con el de hormigas emparentadas de otras regions.
Dulosis is a form of social parasitism in which the workers of 1 species
of ant periodically raid colonies of related species for brood. The plundered
brood is reared in the nest of the parasite by workers of the host species
which serve as the nurse, forager, defense, and construction force for the
mixed colony. Often referred to as slave-making, this type of parasitism is
unique to Formicidae, but has arisen several times independently within
the family (Wilson 1971).
Talbot (1967, 1968), Harman (1968) and Marlin (1968, 1969, 1971) have
reported on the natural history of Polyergus lucidus Mayr in Michigan and
Illinois, and Kwait and Topoff (1983) have recently published on the species'
262 Florida Entomologist 68 (2) June, 1985
behavior on Long Island. This paper reports observations made in 1983 on
3 colonies of the so-called subspecies P. lucidus longicornis Smith near Gaines-
ville, Florida and its host, Formica archboldi Smith. In the opinion of JCT,
the Florida population simply represents the southern end of a spottily dis-
tributed and somewhat variable species; P. lucidus. In view of the morpho-
logical and (as shown below) behavioral indistinctness of the Florida
Polyergus, we refer to these ants henceforth as P. lucidus. This should not
be construed as a formal taxonomic change at this time.
This is the 1st record of F. archboldi as a slave in Polyergus nests. This
Formica is a member of the pallidefulva group, to which most other host
records for P. lucidus belong (Smith 1979).
Florida P. lucidus were observed in a turkey oak-long leaf pine sandhill
community with sparse clumps of wire grass and patches of gopher apple
as ground cover. Other ants common at the site are Formica pallidefulva
Latreille, Camponotus socius Roger, C. floridanus (Buckley), Paratrechina
arenivaga (Wheeler), Leptothorax pergandei Forel, Solenopsis pergandei
Forel, S. geminata (F.), Pogonomyrmex badius (Latreille), Aphaenogaster
floridana M. R. Smith, Pheidole morrisi Forel, and Odontomachus brunneus
(Patton). Prenolepis imparis (Say) is conspicuous from November through
April, but is inactive on the surface during the warmer months.
OBSERVATIONS
RAIDING AND ASSOCIATED BEHAVIORS
On 22 May CJ discovered a column of P. lucidus workers (from Colony
I) crossing a path at 1800 h EDT running very rapidly toward their nest
at the base of a wire grass clump. Each worker bore a pupa from the
raided nest. Upon reaching their own nest, the workers entered it quickly
and did not reappear. In subsequent observations, returning P. lucidus were
always seen to carry stolen F. archboldi brood directly into the nest. This
differs from JCT's oft-repeated observation of P. breviceps Emery in Illinois,
Colorado, and New Mexico, in which the returning raiders hesitate at the
nest entrance, where they drop off the plundered brood, which is then
carried by the F. fusca L. slaves into the nest.
Colony I was visited on several occasions in June and early July but it
was not until 9 July that a raid was observed. On each previous visit, ob-
servations were made from 1600 h or 1700 h until 1900 h, but we saw little
or no P. lucidus activity. On 9 July, the P. lucidus made 4 consecutive raids
on a large colony of F. archboldi. Beginning about 1730 h, 3 Polyergus
workers emerged one by one and milled about the nest entrance for a
minute or two before leaving the nest in various directions. Shortly before
1800 h, one was seen returning hurriedly. By this time, 10 workers were
milling about the entrance. The returning scout entered the nest. After
less than one minute a group of 25 workers set off in a compact column in
the direction from which the scout had come. In a few minutes, they arrived
at and immediately entered the F. archboldi nest. Several dozen F. archboldi,
some bearing brood, scurried out from their nest and took cover under
nearby leaves. The P. lucidus soon reemerged and headed speedily for home.
They entered their nest without hesitation. After 60-90 seconds they re-
emerged, milled about the entrance for a minute or two, then set off again.
On the first raid, 25 workers participated and 21 returned with pupae. (Cor-
Trager & Johnson: Slave-making Ant
responding numbers for the subsequent 3 raids were 31, 25; not counted, 25;
and 36, not counted). Thus between 80 and 100 pupae were robbed from
a single host colony by a work force of no more than 36 P. lucidus workers.
This sort of repeated raiding was called a "compound raid" by Marlin
(1969).
On 10 July, Colony I raided 2 separate F. archboldi colonies (i.e. the
"multiple raid" of Marlin 1969). Both F. archboldi colonies were small,
as only a small number of diminutive F. archboldi individuals were flushed
when the P. lucidus entered their nests, and only about 20 of the Polyergus
returned laden from each raid, some bearing larvae, rather than the usual
pupae. The 1st of the 2 raids occurred between 1735 and 1800 h. The 2nd
raid began at 1815 h and went in precisely the opposite direction from the
1st. The 1st raiding party was accompanied by a dealate P. lucidus queen,
who was frequently at the head of the column, as reported by Marlin (1968).
The queen did not return with the laden workers, but remained in the
raided nest.
On 14 July, F. archboldi slaves from Colony I were observed carrying
brood to a new nest site about 4 meters from the original nest. F. archboldi
slaves carrying brood were followed to the new site. On 15 July, at 1730 h,
24 P. lucidus left in the direction of their old nest, apparently on a normal
raid. Upon arriving at the old nest, the raiders entered and remained in-
side for 4 minutes. Over the next 10 minutes, the P. lucidus emerged 1 by 1
carrying F. archboldi workers held in the characteristic pupoid pose of ants
during social carrying. Two Polyergus were carried by Formica workers in
the same way. This rather spectacular mode of aiding in colony emigration
was reported recently by Kwait and Topoff (1983), who considered such
behavior an adaptive alternative use of the generally implastic raiding
behavior of Polyergus. It is not surprising that Polyergus colonies relocate
periodically, as this may help them avoid local depletion of host colonies
from which to steal brood.
On 16 July, 33 workers from Colony I emerged at 1807 h and headed in
the direction of their old nest. Upon arriving at the old nest, 6 workers
entered it, while the others milled around the entrance. Two minutes later,
the 6 had resurfaced and the procession continued in the same direction.
After 6 minutes, they reached and entered a F. archboldi nest. In less than
a minute 28 P. lucidus bearing pupae, and 1 bearing a larva emerged and
ran quickly toward their nest. The unladen workers straggled behind.
On 15 July, CJ discovered a 2nd P. lucidus colony (Colony II). The work-
ers were crossing another portion of the same path on which the 1st was
found, at 1803 h. At 1820 h they arrived at a large colony of Formica whose
nest was concealed beneath leaves. Thirty-two Polyergus participated in the
raid: 28 returned laden. In a 2nd raid on the same host nest, 26 went out,
and 25 returned of which 24 carried pupae. The missing worker fell into
an antlion pit and was killed on the outward portion of the raid. On 16
July, 30 workers from Colony II left at 1740 h along the same path as the
previous day, but never reached a host nest. By 1800 h all P. lucidus had
straggled back to their nest.
In the summer of 1984, CJ discovered a 3rd P. lucidus colony about 100 m
WNW of Colony II, in the ecotone between the sandhill community in which
Colonies I and II were located and the more mesic woodland to the west.
Colony III was a larger colony; counts made during 1 raid observed by CJ
263
264 Florida Entomologist 68 (2) June, 1985
and 1 observed by JCT both yielded about 45 workers. Colony I was not re-
discovered in 1984, but Colony II was found nesting beneath a wiregrass
clump about 2 m south of its previous nest site. The population of Colony
II had increased since 1983 when it contained 25-30 workers. Several highly
successful compound raids on large F. archboldi colonies by groups of 36-38
P. lucidus workers from Colony II were observed in 1984. A raid in which
the P. lucidus never reached a nest of F. archboldi was observed once each
in Colonies II and III. Several P. lucidus workers from both of these colonies
were caught by antlions while conducting raids.
On several occasions, F. pallidefulva nests or workers were seen near P.
lucidus nests or raiding columns. However, F. pallidefulva is apparently
not enslaved by the P. lucidus population under study, as P. lucidus were
never seen to raid colonies of the former, nor were F. pallidelfulva ever ob-
served among the slave-force of P. lucidus colonies.
NATURAL HISTORY OF F. archboldi
Schneirla (1944) presented information on the biology of F. archboldi
at the Archbold Biological Station in Highlands Co., Florida. In the sand-
hills near Gainesville, Florida, F. archboldi nests at the base of grass clumps,
or in a nest concealed by leaf litter. On 1 occasion JCT saw them build a
small earthen mound about 10 cm in diameter in which they incubated
their sexual pupae, but this was in a shady, more mesic site than that in
which the other observations reported here were made. Based on several
years of collecting in the area, we believe this species prefers scrub or sand-
hill and other more open vegetation in northern Florida.
F. archboldi colonies are very likely to emigrate after disturbance. All
colonies raided by Polyergus had moved away by the next time they were
observed (usually the next day). Also, unraided colonies from which some
of the leaf litter or grass cover was removed, were found to have moved
away within a few days. The nest entrances were always cryptic before
the colonies were disturbed.
In the sandhill community, F. archboldi was a predominant ant observed
foraging on vegetation, especially around nectaries, galls, and homopterans.
They were much more abundant than the number of nests found would
indicate.
Two of the 8 colonies were polygynous; one with 2 dealate females and
one with 4. The colony with 4 had only about 25 small workers and almost
certainly represented one recently founded pleometrotically.
The prey records of F. archboldi are particularly interesting. Foraging
:activity was especially high in the morning and between 1600 h and 1800 h
(especially during the 1st hour of this period). The following records of
prey being carried into F. archboldi nests were accumulated over several
afternoons in late June and July: 8 Odontomachus; 1 Pogonomyrmex; 2 S.
geminata females; 1 S. geminata male; 1 S. pergandei female; 1 tipulid
pupa; 2 small cercopids; 2 scarab beetles; 1 subadult Pictonemobius cricket;
3 unripe Stellaria fruits; 3 Pinus "male cones", and 1 grasshopper fecal
pellet. All of the ants and most of the other insects brought in were still
limp and presumably fresh-killed, though no actual killing was observed. In
the case of the cricket, 4 workers cooperated in carrying the prey toward
the nest from over 1 m away. Two F. archboldi corpses and 1 of P. lucidus
were carried over 2 m away from the nest and discarded, but CJ excavated
Trager & Johnson: Slave-making Ant 265
a nest of F. archboldi in which subterranean refuse heaps contained remains
of numerous Odontomachms workers.
DISCUSSION
In these observations, a good portion of the range of behaviors seen
in more colonies over a much longer total period of time by earlier authors
(see ref. cit.) were seen. The biology of this Florida population of P. lucidus
is remarkably like that of the northern populations. Marlin (1971) sum-
marized the known biology of P. lucidus. To his summary and the data in
Smith (1979) may be added the following points, some of which apply
specifically to the Florida population:
(1) The range of P. lucidus extends south to at least Alachua County,
Florida.
(2) P. lucidus uses F. archboldi as host, within the latter's range in Georgia
and Florida.
(3) Raiding occurs in late spring and early summer. No raids have been
observed after mid-July, despite repeated visits at the appropriate time
of day. It is not known if raids occur before mid-May.
(4) Alate queens and males were observed emerging on hot, cloudless days
in June and early July. No alates were observed after the 1st week of
July. Mating was not observed but the dealate queen mentioned above
seems likely to have been newly mated.
(5) Colony populations were small, with from 25 to perhaps 50 workers
participating in raids. It is believed that the colonies were mature be-
cause they had fully-colored, full-sized workers.
(6) Only a few, perhaps a dozen, raids are conducted each season, though
some or perhaps most are multiple or compound raids, especially the
latter. No raids were observed on most days when the colonies were
watched.
(7) Polyergus workers aid in relocation of nests by performing an emigra-
tion-raid at their old nest and carrying slaves to the new nest site. This
was observed independently by Kwait and Topoff (1983).
(8) On no occasion were the Polyergus observed to kill Formica or even
fight with them. The latter simply fled when their nest was entered by
Polyergus, then reentered after the Polyergus left.
In some of these points, particularly #3, #4, and #5, this southern
population of P. lucidus resembles the Southern California population of
P. breviceps Emery (R. R. Snelling, Natural History Museum, Los Angeles
Co., pers. comm.). The host of the latter is Formica occidua Wheeler, not
previously reported as a slave species. F. occidua, an abundant F. fusca-
group species of southern California, is also enslaved by F. subnuda Emery
in the same region (JCT, unpub. obs.).
Much remains to be known about these and other ants inhabiting the
scrubland and sandhills of Florida, which together constitute some of the
least studied ant communities in North America. Unfortunately, due to
their suitability for development, such habitats are among the most rapidly
disappearing in the region. These interesting areas should be studied
while they last.
ACKNOWLEDGEMENT
We especially thank Daniel P. Wojcik and Ellen C. Kwait, for their
Florida Entomologist 68(2)
June, 1985
constructive criticisms of the manuscript. This is Florida Agricultural Ex-
periment Station Journal Series No. 5742.
REFERENCES CITED
HARMAN, J. R. 1968. Some aspects of the ecology of the slave-making ant
Polyergus lucidus. Ent. News. 79: 217-223.
KWAIT, E. C. AND H. TOPOFF. 1983. Emigration raids by slave-making ants:
a rapid transit system for colony relocation. Psyche 90: 307-312.
MARLIN, J. C. 1968. Notes on a new method of colony formation employed by
Polyergus lucidus lucidus Mayr (Hymenoptera: Formicidae). Trans.
Ill. State Acad. Sci. 61: 207-209.
-- 1969. The raiding behavior of Polyergus lucidus lucidus in central
Illinois (Hymenoptera: Formicidae). J. Kans. Ent. Soc. 42: 108-115.
- 1971. The mating, nesting and ant enemies of Polyergus lucidus Mayr
(Hymenoptera: Formicidae). Amer. Midland Nat. 86: 181-189.
SCHNERILA, T. C. 1944. Results of the Archbold Expeditions. No. 51. Be-
havior and ecological notes on some ants from south-central Florida.
Amer. Mus. Novitates 1261: 1-5.
SMITH, D. R. 1979. Superfamily Formicoidea. pp. 1451, 1453, 1465, 1467. In
Krombein, K. V., P. D. Hurd, Jr., D. R. Smith, and B. D. Burks,
Eds. Catalog of Hymenoptera of America North of Mexico, Vol. 2.
Smithsonian Inst. Press. Washington, D. C.
TALBOT, M. 1967. Slave raids of the ant Polygergus lucidus Mayr. Psyche
74: 299-313.
- 1968. Flights of the ant Polyergus lucidus Mayr. Psyche 75: 46-52.
WILSON, E. 0. 1971. The Insect Societies. Chap. 19. Bellknap Press of
Harvard University Press, Cambridge, MA.
SOCIAL BEHAVIOR IN PASSALID BEETLES
(COLEOPTERA: PASSALIDAE) : COOPERATIVE
BROOD CARE
JACK C. SCHUSTER AND LAURA B. SCHUSTER
Departamento de Biologia
Universidad del Valle de Guatemala
Apartado Postal 82
Guatemala, GUATEMALA, C. A.
ABSTRACT
A brief summary is given concerning passalid social behavior in relation
to their life cycle. Passalid pairs defend log tunnels and remain with off-
spring from egg to adulthood. Parent-offspring cooperation involving care
of other offspring is a step in the evolution of eusociality. Young adult
passalids cooperated with their parents in repair of sibling pupal cases. Co-
operative brood care between parents and juveniles has not been reported
previously for non-Hymenopterous or non-Isopterous arthropods. The pres-
ence of overlap of generations and cooperative brood care by at least
temporarily non-reproductive adult individuals in certain passalid species
suggest that we might consider these passalids to possess one of the highest
levels of subsocial behavior known for arthropods. Habitat, trophic rela-
266
Schuster & Schuster: Passalid Brood Care
tions between individuals, and sex determination mechanisms suggest
parallels with the evolution of termite sociality.
RESUME
Se resume brevemente lo que se conoce acerca del comportamiento social
de passalidor en relaci6n a su ciclo de vida. Parejas de pasilidos difienden
tineles en palos y se quedan con su prole desde huevo hasta adulto. Co-
operaci6n entire padres y prole involucrando cuidado de otra prole, es una
etapa en la evoluci6n de la eusocialidad. J6venes adults cooperaron con sus
padres en la reparaci6n de capullos pupales de sus hermanos. Cuidado de la
cria en cooperaci6n entire padres y juveniles no ha sido reportado anterior-
mente para los artropodos no-Hymenopteros o no-Isopteros. La presencia
de traslape de generaciones y cooperaci6n entire adults y prole que son
temporalmente no-reproductivas en algunas species de pasalidos, sugiere
que estos pasilidos poseen uno de los niveles conocidos mAs altos de com-
portamiento subsocial entire los artr6podos. Habitat, relaciones tr6ficas entire
individuos y mecanismos de determinaci6n de sexo, sugieren paralelas con
la evoluci6n de la eusocialidad en termitas.
Cooperative broad care, overlap of parental and offspring generations,
and the presence of reproductive castes are the basic characteristics which
define truly social (eusocial and hypersocial) behavior in arthropods (Batra
1966, 1977). These high levels of social behavior are recognized among the
arthropods primarily in the Hymenoptera and Isoptera. Some arthropods
have forms of subsocial or quasisocial behavior with 1 or rarely 2 of these
characteristics developed to varying degrees (Wilson 1971, Eickwort 1981).
Passalid beetles are among the most highly subsocial insects because they
possess, in at least some species, both overlap of generations and, as we
report here, cooperation in brood care between parent and offspring. Young
adult passalids cooperate with their parents in repair of sibling pupal cases.
Cooperative brood care is rare (unknown?) for arthropods other than
Hymenoptera or Isoptera. Habitat, trophic relations between individuals,
and sex determination mechanisms suggest parallels with the evolution of
termite sociality.
The family Passalidae contains approximately 500 species of primarily
tropical, wood-eating beetles that tunnel in rotting logs (Reyes-Castillo
1970, Schuster 1978). One beetle (either sex) arrives at a log and begins
a tunnel. The other beetle which will form the pair arrives later. The
beetles are monogamous and the pair remains together at least through
the development of the first brood. They will defend the tunnel against
other passalid intruders (Schuster 1975). Acoustical communication is
highly developed in the colony, especially associated with courtship and
aggression. One species has at least 17 signals, more than is known from
any other arthropod (Schuster 1983).
Eggs are placed in a nest of finally triturated wood in the tunnel.
Though Krause and Ryan (1953) mention 100 eggs and juveniles of the
first larval instar in a nest of Odontotaenius disjunctus (Illiger) (formerly
Passalus cornutus Fabricius and Popilius disjunctus Ill.), Gray (1946)
noted nests of this species usually contain 20-35 eggs. In various countries
we examined a total of 28 natural passalid nests by carefully dissecting the
tunnel systems; the maximum number of progeny (eggs and young larvae)
267
268 Florida Entomologist 68 (2) June, 1985
in a nest was 42 for Chondrocephalus purulensis (Bates) in Guatemala. In
some tropical species a pair can produce 3, and perhaps 4, egg clutches in
a year (Schuster 1975). We observed courtship of 0. zodiacus (Truqui) in
the presence of third instar larvae; occasionally, we found pupae and eggs
in a tunnel system without any intermediate larval stages. Apparently,
therefore, when a brood is in or near the pupal state, another egg clutch may
be produced. It is not necessary, however, for the male to be present (though
apparently he usually is) for subsequent egg clutch production. A female
Publius agassizi (Kaup) collected in May and maintained completely iso-
lated from other passalids produced a clutch of fertile eggs at 4 months and
another a year after capture. Nevertheless, it is rare to find single beetles
in a tunnel system except at the initial stage of excavation.
In Passalidae, black (mature) adults are found in tunnels with all onto-
genetic stages, including red generall) adults. In 76 passalid tunnel systems
containing juveniles of 37 species in Peru, Costa Rica, Mexico and Guate-
mala, mature adults were present in all except 2 systems. Of 17 systems
with at least 1 general adult, 16 also contained at least 1 mature adult.
Since general adults require a few weeks to many months to blacken en-
tirely, this suggests a minimal duration of parent-adult progeny contact.
Usually, only completely black adults migrate (Schuster 1975). Of 51 mi-
grating passalids captured in Guatemala, 40 were black, 11 were inter-
mediate in color and none were red. The presence of more than 2 black adults
in 1 tunnel system indicates that migration may not necessarily occur im-
mediately upon blackening. This inference is strengthened by the aggressive
behavior of colonists toward intruders, reducing the probability of foreign
beetles joining the colony; thus all black beetles in a colony should be either
parents or progeny. The maximal duration of generation overlap may depend
on resource availability and consumption rate, or on adult longevity. Adults
live more than 2 years in the field, and in the laboratory a pair of Passalus
affinis (Percheron) survived 4 years. Individuals of P. punctiger Lepeletier
& Serville and 0. zodiacus continued reproducing after 2 years.
Very little is known concerning the life and behavior of the larvae until
pupation. A third larval instar pupates in a case of fine-textured, compacted
excrement and wood shreds constructed with adult aid (Fig. 1). This case
may be important in protecting the pupa from predation or parasitism.
Reduviids and tachinids are known to attack passalids (Schuster 1975).
About 5 days prior to pupation, the larva ceases feeding, becomes whiter,
and enters a pre-pupal stage. In the absence of adults, the prepupa will
roll over and over, forming a depression in the feces and wood shreds. It will
pupate in this depression. When adults are present, they will aid the larva
in pupal case construction, as described by Miller (1932) from laboratory
observations of 0. disjunctus, by piling case material on the prepupa and
shaping it from the outside. Two or more adults may work on the same
case concurrently, or a single adult may work alone. Males and females may
participate in construction.
The presence of parental brood care and generation overlap allows the
possibility of cooperative brood care between parents and adult offspring,
apparently quite rare outside the Hymenoptera and Isoptera. In Passalidae,
parents, general adults, pupae and older larvae are commonly found together
in the same tunnel system, a situation obviously conducive to cooperative
brood care. In some cases, even greater overlap occurs, e.g. a chamber ap-
Schuster & Schuster: Passalid Brood Care
Fig. 1. Passalus punctiger-pupal case containing prepupa.
proximately 18 cm long in a Mexican log contained 22 Heliscus tropicus
(Perch.) eggs, 4 first instar and 1 third instar larvae, 3 pupae, 10 general
adults, and 3 black adults. Passalid iteroparity augments the potential for
cooperation.
Evidence of sibling cooperation has been observed in pupal case con-
struction. Miller (1932) observed 2 or more adults of the same sex construct-
ing pupal cases together, but he did not give any indication of their genetic
relationships. We collected 1 black and 2 general Popilius haagi (Kaup)
adults and 3 larvae from the same tunnel system. Two of the larvae pupated
and became adults within a week before the construction of the pupal case
for the third larva. The new adults were not seen to aid the construction
of the third case though construction was not observed continuously. There-
fore, on 1 occasion 7 days, and another 9 days, after case construction, we
made a hole 3 x 5 mm in the side of the new pupal case. Both times it was
repaired by older beetles working together with a newly emerged beetle
pushing frass with their mandibles and head to and against the pupal case.
In the second case, the general beetle completed the reconstruction alone
after the others had stopped working. A general adult emerged from the
case 15 days later.
In a similar experiment with Verres hageni Kaup, we completely de-
stroyed a case containing a prepupa. A black adult and 2 general adults
269
270 Florida Entomologist 68 (2) June, 1985
worked together in completely reconstructing the case. The slightly darker
general adult reconstructed much more than did the very red adult. All
were from the same log.
In a situation with Passalus punctiger a pupal case was damaged several
times in the presence of the black adult that had constructed it and a
general adult 3 days out of its case. Only the black adult repaired the case.
However, when the black adult was removed a rough case was constructed
by the general adult within 21 hours; the case was well constructed within
33 hours.
In these species, as well as 2 others (Chondrocephalus purulensis and
P. punctatostriatus (Percheron)) with which pupal case destruction experi-
ments were done only with black or dark intermediate adults, the mature
adults often became quite active immediately on contacting the destroyed
sections of a case. The general red adults were usually slower to begin con-
struction.
These observations indicate that a beetle may cooperate with other
siblings and/or its parents in the construction and repair of a sibling's pupal
case. The only trait, therefore, that can separate passalids from eusocial
insects is their lack of castes. In adult passalids, external morphological
differences are minimal or non-existent, even between sexes, except for
general redness. Exactly when adults become sexually mature is unknown.
Young adult males are not sexually mature (Virkki and Reyes-Castillo
1972); they have spermatogonia but lack spermatozoa (Virkki 1965). These
factors would make it difficult to distinguish if possible castes (differing only
in degree of ovarian development) do occur in some insects (Plateaux-Qu6nu
1960,1962).
The rate of ovarian development is unknown. Courtship occurred 3
months after male and female pupal ecdysis in P. punctiger and 4 months
after ecdysis of both sexes in 0. disjunctus, which may indicate maturation
by this time. Reproduction by either sex can occur 10 to 11 months after
pupal ecdysis in 0. disjunctus (Schuster 1975).
What factors may have influenced the evolution of such a high level of
sociality in passalids? The haplodiploidy (males haploid) sex determination
mechanism of Hymenoptera is thought to predispose this group toward
the evolution of sociality (Hamilton 1964). Trophic relationship regarding
transmission of mutualistic intestinal protozoa and/or bacteria in some
termites may be a key factor in the evolution of termite eusociality (Howse
1970). Termites pass their protozoa throughout the colony by anal trophal-
laxis, the ingestion of anal liquids by other colony members. Repeated anal
trophallaxis is necessary because each time a worker molts it loses its in-
testinal symbionts.
In many respects, Passalidae resemble termites and their probable an-
cestors the cryptocercid roaches (Nalepa 1984) more than Hymenoptera.
Termites have a conventional genic sex determination mechanism (Hamilton
1972), as do passalids, which have either XY variants or XO, depending on
the species (Virkki and Reyes-Castillo 1973). Monogamy in passalids, as in
termites, should result in a high degree of relatedness among individuals of
a given colony. Though passalid intestines have no cellulose-degrading proto-
zoa, they do have a well developed flora and fauna, especially various fungi
and nematodes (Lewis 1926). Passalids fed only rotting wood lose weight
and die much sooner than those that eat passalid feces or previously tritu-
Schuster & Schuster: Passalid Brood Care
271
rated wood which has been partially decomposed by microorganisms (Mason
and Odum 1967). For this reason alone, it would be advantageous for the
larvae to remain near the adults. This may also explain why the eggs are
placed in a nest of finely chewed wood. Ohaus (1900) suggests that the
larval jaws are too weak to eat wood directly, but Heymons (1929) refutes
this on the basis of morphological and behavioral studies in the laboratory.
Instead, the finely shredded wood exposes a greater surface area to attack
by wood-digesting microorganisms. More nutrients then become available
to the newly hatched larvae, either as by-products of this digestion or in
the bodies of the microorganisms ingested.
Both termites and passalids live in rotting wood. Dead trunks harbor a
large number of subsocial species of arthropods and are apparently the site
of origin of at least 2 truly social groups: ants and termites (Hamilton
1978). Organisms in such stable, structured "bonanza" microhabitats are
usually subjected to K-selection, which tends to favor longer life, large
mature size, iteroparity, and small broods (Wilson 1975)-all characteristic
of Passalidae. These, in turn, tend to favor the evolution of increased
parental care (Wilson 1975).
The presence of overlap of generations and cooperative brood care by
at least temporarily non-reproductive adult individuals in certain passalid
species suggest that we might consider these passalids to possess 1 of the
highest levels of subsocial behavior known for arthropods.
END NOTE
We thank S. W. T. Batra, M. Dix, J. E. Lloyd, P. Reyes-Castillo, T. J.
Walker, R. S. Wilcox, and an anonymous reviewer for criticisms of the
manuscript; P. Reyes-Castillo for aid in insect identification; R. L.
Enriquez, A. Valenzuela, E. Valenzuela and O. Molina for typing the manu-
script; and the Organization for Tropical Studies; U. S. Peace Corps-Peru;
Universidad Nacional Agraria de la Selva, Tingo Maria, Peru; University
of Florida; and the Universidad del Valle de Guatemala for their support
and research opportunities provided. Jack Schuster is a Research Associate,
Florida State Collection of Arthropods, Department of Plant Industry
Gainesville, FL.
REFERENCES CITED
BATRA, S. W. T. 1966. Nests and social behavior of Halictine Bees of India
(Hymenoptera: Halictidae). Indian J. Ent. 28: 375-93.
-- 1977. Bees of India, their behavior, management and a key to the
genera. Oriental Insects. 11: 289-324.
EICKWORT, G. C. 1981. Presocial insects. Pages 199-280 in H. Herman, ed.
Social Insects. Academic Press, New York.
GRAY, I. E. 1946. Observations on the life history of the horned passalus.
American Midl. Nat. 35(3): 728-746.
HAMILTON, W. D. 1964. The genetical evolution of social behavior. J. Theoret.
Biol. 7: 1-52.
-- 1972. Altruism and related phenomena, mainly in social insects. A.
Rev. Ecol. Syst. 3: 193-232.
----. 1978. Evolution and diversity under bark. Pages 154-75 in L. A.
Mound and N. Waloff, eds. Diversity of Insect Faunas. Blackwell,
London.
272 Florida Entomologist 68 (2) June, 1985
HEYMONS, R. 1929. Vtber die biologie der Passaluskafer. Zeit. Morph. Oko-
logie Tiere. 16: 74-100.
HOWSE, P. E. 1970. Termites: A Study in Social Behavior. Hutchinson
Univ. Libr., London.
KRAUSE, J. B. AND M. T. RYAN. 1953. The stages of development in the
embryology of the horned passalus beetle, Popilius disjunctus Illiger.
Ann. Ent. Soc. America 25: 1-20.
LEWIS, H. C. 1926. The alimentary canal of Passalus. Ohio J. Sci. 26: 11-21.
MASON, W. H. AND E. P. ODUM. 1969. The effect of coprophagy on retention
and bioelimination of radionuclides by detritus-feeding animals. Pages
721-4 in D. Nelson and F. Evans, eds. Proceedings of the Second
National Symposium on Radioecology, Ann Arbor, Michigan.
MILLER, W. C. 1932. The pupa-case building activities of Passalus cornutus
Fabr. (Lamellicornia). Ann. Ent. Soc. America 25: 709-712.
NALEPA, C. 1984. Colony composition, protozoan transfer and some life
history characteristics of the woodroach Cryptocercus punctulatus
Scudder (Dictyoptera: Cryptocercidae). Behav. Ecol. Sociobiol. 14:.
273-9.
OHAUS, F. 1900. Bericht fiber eine entomologische Reise nach Central-
brasilien. Stett. Ent. Zeit. 61: 164-273.
PLATEAUX-QUENU, C. 1960. Nouvelle preuve d'un determinisme imaginal des
castes chez Halictus marginatus. Brulle. Cited in E. O. Wilson. The
Insect Societies. Belknap Press, Cambridge, Mass.
---. 1962. Biology of Halictus marginatus Brull&. Cited in E. 0. Wilson.
The Insect Societies. Belknap Press, Cambridge, Mass.
REYES-CASTILLO, P. 1970. Coleptera: Passalidae: morfologia y division en
grandes grupos; g6neros americanos. Folia Ent. Mex. 20-22: 1-240.
SCHUSTER, J. C. 1975. Comparative behavior, acoustical signals, and ecology
of New World Passalidae (Coleoptera). Ph.D. diss., Univ. Florida
127 p.
-- 1978. Biogeographical and ecological limits of New World Passa-
lidae (Coleoptera). Colept. Bull. 32(1) : 21-8.
-- 1983. Acoustical signals of passalid beetles: complex repertoires.
Florida Ent. 66(4): 486-96.
VIRKKI, N. 1965. Insect gametogenesis as a target. Agr. Sci. Rev. 3(3) : 24-
37.
--- AND P. REYES-CASTILLO. 1972. Cytotaxonomy of Passalidae (Coleop-
tera). An. Esc. Nac. Cienc. Biol., M6xico. 19: 49-83.
WILSON, E. 0. 1971. The Insect Societies. Belknap Press, Cambridge, Mass.
1975. Sociobiology. Belknap Press, Cambridge, Mass.
Sivinski & Webb: Caribfly Acoustic Morphology
273
SOUND PRODUCTION AND RECEPTION IN THE
CARIBFLY, ANASTREPHA SUSPENSE
(DIPTERA: TEPHRITIDAE)
J. SIVINSKI AND J. C. WEBB
Insect Attractants, Behavior, and Basic Biology Research Laboratory,
Agricultural Research Service, U. S. Department of Agriculture,
Gainesville, FL 32604 USA
ABSTRACT
Virgin female Anastrepha suspense (Loew) with aristae removed failed
to respond to recorded male "calling" song to the same extent as intact fe-
males. However, removal of aristae did not change female response to an-
other sound known to modify behavior: the "precopulatory" song sung by
mounted males. Thus, aristae are possibly not the sole organs of sound/
vibration reception. Virgin females without aristae are attracted to male-
produced pheromones and the aristae bear no evidence of chemosensilla.
These organs appear to be involved only in mechanoreception. Apparently
the male songs of A. suspense are produced solely by wings because their
sound pressure levels increase in proportion to the amount of wing surface,
and there are no obvious morphological features that might make up a wing
powered stridulatory mechanism. There is a slight sexual dimorphism in
wing shape (male wings were more oval). Comparisons among tephritids
with various wing shapes and courtship signals suggest that the di-
morphism might be due to male wing modification for sound production.
RESUME
Hembras virgenes de Anastrepha suspense (Loew) con las aristas re-
movidas, no respondieron en el mismo grado que las hembras intactas al
canto grabado de Ilamada del macho. Sin embargo, al quitarle las aristas,
no cambi6 la respuesta de las hembras a otros sonidos conocidos como
modificadores de comportamiento, que es las canci6n "pre-copulatoria" can-
tada por machos apareados. De aqui que las aristas no son posiblemente los
finicos 6rganos de recepci6n de la vibraci6n de sonidos. Hembras virgenes
sin aristas son atraidas por feromonas producidas por machos y las aristas
no muestran evidencia de "chemosensilla". Estos 6rganos parecen estar
involucrados solamente como receptores mecanicos. Aparentemente, el canto
de los machos de A. suspense son producidos solamente por las alas, puesto
que los niveles de la presi6n del sonido aumenta en proporci6n a la cantidad
de superficie del ala, y no hay ningin rasgo morfol6gico que pueda hacer un
mecanismo de estridulaci6n hecho por la fuerza motriz del ala. Hay un
pequefio dimorfismo sexual en la forma del ala (las alas de los machos son
mas ovales). Comparaciones entire tefritidos con varias formas de alas y
sefiales de cortejo, sugieren que el dimorfismo puede ser debido a modifica-
ciones en el ala del macho para producer sonidos.
A few flies make sounds during courtship and territorial defense (Burk
1981). The best known are the "love songs" of Drosophila spp. (Bennet-
Clark and Ewing 1970, see also contributions in Huettel 1985). However,
there is information accumulating on the function and structure of acoustic
signals in the Caribbean fruit fly, (caribfly) (Anastrepha suspense [Loew])
274 Florida Entomologist 68 (2) June, 1985
(Diptera: Tephritidae). Caribflies produce 2 sounds in sexual context: the
calling song, consisting of repeated pulse trains (bursts) broadcast from
territories on host-plant leaves, and the precopulatory song emitted just
prior to, and during insertion of the aedeagus (Webb et al. 1976). The
calling song attracts females in field cages (Webb et al. 1983a) and in-
creases the activity of virgin, but not of mated, females in the laboratory
(Sivinski et al. 1984). Precopulatory song influences male acceptance by
females and may be a means of advertising male vigor. Both loud volume
and a continuous, non-pulsed structure increase the likelihood that a male
will complete a coupling (Sivinski et al. 1984).
The means by which tephritid flies perceive these sexual messages have
not been previously examined, though in another acalypterate family, the
Drosophilidae, sound is perceived through the vibration of the aristae
stimulating Johnston's organ on the 2nd antennal segment (e.g., Manning
1967, Ewing 1978). We show here that the caribfly sounds are produced
by the wings and some are received via the aristae, but that these antennal
structures may not be the sole organs of hearing.
METHODS
SOUND RECEPTION
In order to determine the acoustic sensitivity of the aristae, adult flies
were cold-anesthetized. Half of the anesthetized flies had at least 90% of
their aristae removed with forceps, while the rest served as controls. Pre-
vious experiments had shown that virgin females respond to calling song
with increased flight and walking (Sivinski et al. 1984). Differences in the
response to sexual signals of virgin females with and without aristae were
searched for in the following manner. Two observers, in an anechoic
chamber, simultaneously measured activity in an experimental and in a
control replication by counting the number of times 25 flies in a 20 cm x 20
cm x 20 cm screen wire cage crossed a line bisecting the cage.
Both cages had a speaker simultaneously emitting the same recorded
calling song at a sound pressure level (SPL) (odB re 20 /pa) of 55 dB at
cage-center (note that due to meter inertia calling song SPLs are estimates
rather than precise measurements). Counts were made during 6 alternating
5-min periods of broadcast and silence. Ten replicates were performed.
To determine if aristae might have additional chemosensory properties,
15 virgin 9 9 with and 15 without aristae were placed in an olfactometer,
a device that traps females moving in the direction of an odor stimulus.
Males, substantially muted by wing removal, served as a pheromone source.
Dealation was an attempt to avoid confusion of signal modes, i.e., to pro-
vide both supposedly deaf and hearing females with a similar set of
signals. Ten replicates were made.
EFFECT OF ARISTAE REMOVAL ON COPULATORY BEHAVIOUR
Precopulatory song intensity influences female reception of mounted
males (Burk & Webb 1983, Sivinski et al. 1984). It seemed reasonable that
if aristae removal deafened females, such flies might be less likely to allow
penetration, or that males would have to sing more loudly, or for longer
periods of time to overcome female resistance. We observed intact and
Sivinski & Webb: Caribfly Acoustic Morphology
275
females without aristae enclosed individually with a male fly in a 7.5 cm x
7.5 cm screen wire cylinder. The number of rejections a male suffered, the
time between introduction and copulation, and the duration of the pre-
copulatory song were recorded.
Precopulatory song SPL was measured with a 12.7 mm Briiel & Kjaer
Model 4145 condenser microphone held at 2.5 mm from the flies, and
coupled through a cathode follower to a Briiel & Kjaer Model 2608 micro-
phone amplifier and SPL meter. Note that the SPL of the relatively con-
tinuous precopulatory song can be measured without the problem of meter
inertia that plagues attempts to quantify the periodic calling song.
THE EFFECT OF CHANGES IN WING AREA ON SOUND PRODUCTION
We clipped the wings of male caribflies resulting in losses of 40, 60, 85 and
95% of the wing area (N 1oo percent = 119, N60 percent = 6, N40 percent = 7,
N15 percent = 2, N5 percent = 3). These percentages were determined by
cutting a wing image projected by a microprojector onto a piece of paper.
The resulting model was cut in the same manner as the wings and the frag-
ments weighed. Clipped males were placed with virgin females and the
SPL of their precopulatory songs measured in the previously described
manner.
SEXUAL DIMORPHISM IN WINGS
If wings are organs of sound production, it might be expected that their
structure would be specialized for singing in the more acoustical sex (males).
The shape (length/width) of male and female wings were compared by
determining the width of the wings measured through the cross vein that
separates the 2nd dorsal and the 2nd basal cells, to the wing margins and
the length of the distal portion of the wing from the junction of the pre-
viously mentioned cross vein with the M1+2 vein to the distal wing margin.
Measurements were made by 2 methods, with a micrometer mounted in a
stereomicroscope (n 8 & = 21, n 9 9 = 20), and by microprojector that
projected an enlarged image on a piece of paper (n & S = 26, n 9 9 =
26) (see Sharp 1979). In order to search for allometric relationships be-
tween size and wing shape, the sizes of flies were determined in the micro-
meter-gathered data by measuring the length of a hind femur. The wings
of another singing fruit fly Toxotrypana curvicauda Gerstacker and a silent
species Rhagoletis pomonella (Walsh) were measured with a micrometer so
that our sound production hypothesis could be tested by comparison (NTp
8 = 21, NTp 2 = 28; N1p 8 = 10, NRP 9 = 10, see respectively
Landolt et al. 1985 and Prokopy and Bush 1973 for details of courtship).
RESULTS
SOUND RECEPTION
Virgin female flies with aristae were more active during periods of
calling-song broadcast than during alternating periods of silence (Wilcoxon
paired test P < 0.05). There was no significant difference in the activities
during sound and silence of females with their aristae removed (P > 0.25).
The ability of flies without aristae to move about was not affected adversely
by handling during the operation. Likewise, there was no difference in
Florida Entomologist 68 (2)
the response of females with and without aristae to the pheromones of
muted males (28 with and 39 without aristae were captured P > .05).
Electronmicrographs of aristae showed none of the surface features (e.g.,
pits) associated with chemoreception. When this lack of sensilla is coupled
to the undiminished response to distance pheromone by females without
aristae, it seems that aristae in caribflies are not chemosensitive and are
primarily mechanoreceptors.
EFFECTS OF ARISTAE REMOVAL ON COPULATORY BEHAVIOUR
There was no indication that removal of aristae influenced copulatory
behavior. Females without aristae were no more apt than intact females
to reject mounted males (28% of 58 & S mounting intact females were
rejected at least once, compared to 31% of 51 & S mounting aristaeless fe-
males). Nor did intact females accept males more rapidly (X 11.9 min from
introduction vs. 13.3 min P = 0.42), have longer matings (x 41.9 min vs.
39.8 min P = 0.49), or have suitors that sang shorter songs (x 71.8 sec vs.
55.9 sec P = 0.41).
THE EFFECT OF CHANGES IN WING AREA ON SOUND PRODUCTION
The sound pressure level of a male precopulatory song decreased with
decreasing surface area of the wing, suggesting that the wing is either the
agent of sound production or the power source for a sound producing organ
(r2 = 0.88, P < 0.01), note that the last clipping leaves ca. 5% of the
wing producing ca. 6% of the original SPL). There is no evidence of morpho-
logical features that might make up a stridulatory organ and it thus seems
likely that caribfly songs are sung only with the wings with perhaps some
additional vibrations of thoracic structures (see Esch and Wilson 1967).
SEXUAL DIMORPHISM IN WINGS
The ratio of wing length to width is significantly greater in female
flies, i.e., the wings of males are slightly stubbierr" (micrometer obtained
ratios X 8 = 1.65, x 9 = 1.69, Wilcoxon rank-sum test P = 0.02, P .=
0.01; microprojector X $ = 1.68, K 9 = 1.72, P < 0.01). This is not due
to an allometric relationship; that is, there is not a change of wing shape
with size that would generate a de facto sexual dimorphism since males are
generally smaller. In fact, there is an opposite relationship in female flies
where the longer the femur the less the length of the wing relative to
width (r = -.57, P = 0.009). There is no significant relationship between
size and shape in males. In the papaya fruit fly, T. curvicauda, which also
produces wing generated courtship sounds, male wings are again stubbier
(x & = 1.90, X 9 = 2.13, P < 0.0001). However the sexually silent
apple maggot, R. pomonella, has no sexual dimorphism in wing shape (x $
= 1.60; X 9 = 1.59, P = 0.64). The greater surface area of male wings
of a given length could be a means of displacing more air and hence pro-
ducing a louder sound.
DISCUSSION
Removal of aristae inhibited female response to calling song but does
276
June, 1985
Sivinski & Webb: Caribfly Acoustic Morphology
277
not obviously affect coupling, a process known to be influenced by precopula-
tory song. Perhaps the simplest way of resolving these conflicting results is
to posit at least 2 sites of sound/vibration reception. It is plausible that
the sound produced by a male in physical contact could be perceived through
mechanoreceptors on the female body, legs and/or wings. If so, perhaps
the removal of organs adapted for sensing air displacement (i.e., aristae)
would not significantly affect reception of precopulatory signals or subse-
quent female behavior.
Averhoff et al. (1979) have argued that the aristae of Drosophila bear
chemosensitive sensilla and that changes in behavior recorded in Drosophila
after removal of antennae may not be due to deafness, but an inability to
perceive pheromones. Both bioassay and micromorphological examination
failed to find any evidence of chemosensitivity in caribfly aristae.
Evidence suggests that the caribfly sounds are solely or principally
generated by wing movements. It is tempting to ascribe any differences in
the wings of the sexes to modification for male sound production. However,
sexual dimorphism in wing shape also might increase the signaling surface
for visual displays, or reflect changes in wing loading evolved because of a
dimorphism in flight activity. Comparing wing shape in tephritids with
different signaling systems might help illuminate the functions of sexual di-
morphism in wing shape. The reader will recall that male wings are more
oval in the singing species A. suspense and T. curvicauda. However, R.
pomonella, which moves its wings in courtship but does not sing has no
such sexual dimorphism. Male wings in the Mediterranean fruit fly,
Ceratitis capitata (Wied.), another acoustic singer that produces both
stridulatory and wing generated sounds are again stubbier than those of
the female (Keiser et al. 1973, Webb et al. 1983b). Sharp (1979) has deter-
mined wing width and length using different measurements than ours for
a number of tephritids. These can be used for cautious comparisons with
our data (note that these data would show no sexual dimorphism in A.
suspense). Dacus spp. acoustic signals are due to stridulation (Monro
1953). D. cucurbitae (Coquillett) and D. oleae (Gmelin) have wing length/
width ratios that are opposite A. suspense, while D. dorsalis has no apparent
sexual dimorphism. Thus the comparative evidence suggests that ovalness
in male wings may have an acoustic function.
ACKNOWLEDGMENTS
T. Burk, C. Calkins, T. Forrest and J. Sharp made many improvements
of the manuscript which was professionally typed by E. Turner. T. Carlysle
prepared and interpreted the electron micrographs. Mention of a commercial
or proprietary product does not constitute an endorsement by the USDA.
REFERENCES CITED
AVERHOFF, W. EHRMAN, L., J. E. LEONARD, AND R. H. RICHARDSON. 1979.
Antennal signal receptors in Drosophila mating. Biol. Zbl. 98: 1-12.
BENNET-CLARK, H. C. AND A. W. EWING. 1970. The love song of the fruit
fly. Sci. America 223: 84-92.
BURK, T. 1981. Signalling and sex in acalypterate flies. Florida Ent. 64:
30-43.
BURK, T. AND J. C. WEBB. 1983. Effect of male size on calling propensity,
song parameters, and mating success in Caribbean fruit flies, An-
278 Florida Entomologist 68 (2) June, 1985
astrepha suspense (Loew) (Diptera: Tephritidae). Ann. Ent. Soc.
America 76: 678-682.
ESCH, H., AND D. WILSON. 1967. The sounds produced by flies and bees. Zeit.
verg. Physiol. 54: 256-267.
EWING, A. W. 1978. The antenna of Drosophila as a "love song" receptor.
Physiol. Ent. 3: 33-36.
HUETTEL, M. (1985). Evolution of Invertebrate Behavior. Plenum Press,
New York. (In press)
KEISER, I., R. M. KOBAYASHI, D. L. CHAMBERS, AND E. L. SCHNEIDER. 1973.
Relation of sexual dimorphism in the wings, potential stridulation,
and illumination to mating of Oriental fruit flies, melon flies, and
Mediterranean fruit flies in Hawaii. Ann. Ent. Soc. America 66:
937-941.
LANDOLT, P. J., R. HEATH, AND J. R. KING. 1985. Behavioral responses of fe-
male papaya fruit fly Toxotrypana curvicauda Gerstaecker (Diptera:
Tephritidae) to male produced sex pheromone. Ann. Entomol. Soc.
America (in press).
MANNING, A. 1967. Antennae and sexual receptivity in Drosophila melano-
gaster females. Science 158: 136-137.
MONROE, J. 1953. Stridulation in the Queensland fruit fly Dacus (strumeta)
tryoni Frogg. Australian J. Sci. 16: 60-62.
PROKOPY, R. J., AND G. L. BUSH. 1973. Mating behavior of Rhagoletis
pomonella (Diptera: Tephritidae) IV. Courtship. Canadian Entomol.
105: 873-891.
SHARP, J. 1979. A method to determine wing dimensions of insects. Florida
Ent. 62: 69-71.
SIVINSKI, J., T. BURK, AND J. C. WEBB. 1984. Acoustic courtship signals in
the caribfly Anastrepha suspense (Loew). Anim. Behav. 32: 1011-
1016.
WEBB, J. C., J. L. SHARP, D. L. CHAMBERS, J. J. McDow, AND J. C. BENNER.
1976. Analysis and identification of sounds produced by the male Carib-
bean fruit fly, Anastrepha suspense. Ann. Ent. Soc. America 69: 415-
420.
WEBB, J. C., T. BURK, AND J. SIVINSKI. 1983a. Attraction of female Carib-
bean fruit flies (Anastrepha suspense (Loew)) to males and male
produced stimuli in field cages. Ann. Ent. Soc. America 76: 996-998.
WEBB, J. C., C. O. CALKINS, D. L. CHAMBERS, W. SCHWIENBACHER, AND K.
Russ. 1983b. Acoustical aspects of behavior of Mediterranean fruit
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Gonzalez et al.: Melittobia pheromone 279
A SEX PHEROMONE IN MALES OF MELITTOBIA
AUSTRALICA AND M. FEMORATA (HYMENOPTERA:
EULOPHIDAE)
JORGE M. GONZALEZ, ROBERT W. MATTHEWS, AND JANICE R. MATTHEWS
Department of Entomology
University of Georgia
Athens, GA 30602 USA
ABSTRACT
A 4-choice arena was used to test for evidence of a volatile male-produced
attractant in macropterous and brachypterous forms of 2 closely related
parasitic wasps, Melittobia australica Girault and M. femorata Dahms.
Virgin females of both species and forms were strongly attracted to freshly
killed mashed and intact males and to living males. They were unresponsive
toward males which had been dead for at least 5 days and toward empty
controls. Mated females were indifferent to males, regardless of male con-
dition. Bioassays implicated the abdomen as the source of the male sex
pheromone in both species.
RESUME
Un scenario donde se le daba 4 oportunidades para escoger, fue usado
para probar la presencia de un compuesto volatile producido por los machos,
el cual atrae a hembras macropteras y brachypteras de dos species de
avispas parasiticas cercanamente relacionadas, Melittobia australica Girault
y M. femorata Dahms. Hembras virgenes de ambas species y formas fueron
fuertemente atraidas hacia machos recientemente muertos, tanto machacados
como intactos, y hacia machos vivos. Ellas no respondieron hacia machos que
tenian al menos 5 dias de muertos o hacia el testigo. Hembras previamente
apareadas no fueron atraidas hacia los machos, indiferentemente de la con-
dici6n de los mismos. Ensayos biol6gicos con ambas species indicaron que
el lugar de origen de dicha feromona masculina estA en el abdomen.
Melittobia is a genus of small parasitic wasps whose extreme sexual
dimorphism and skewed sex ratios have attracted the attention of many
scientists (Dahms 1984a). Hermann (1971) kept virgin Melittobia females
in gelatin capsules separate from capsules with males. Surprisingly, these
females chewed through their own capsules and went to the capsules with
males; there, they chewed their way in or became trapped between top and
bottom layers of the males' capsules. Based on these observations, Hermann
et al. (1974) suggested the presence of a "male calling pheromone" in Melit-
tobia chalybii (= australica). An apparent male pheromonal role in court-
ship of 2 Melittobia species was also noted by Evans and Matthews (1976).
The present study was undertaken to further determine the nature of the
presumed attractant.
MATERIALS AND METHODS
Wasps. The 2 species in this study, Melittobia australica Girault and M.
femorata Dahms, were obtained from cultures maintained in our laboratory
Florida Entomologist 68 (2)
June, 1985
at the University of Georgia. Originally collected in 1983 as parasites of
the mud-dauber, Trypoxylon politum Say, from the vicinity of Athens,
Georgia, the wasps were identified according to Dahms (1984b).
Virgin females were isolated as late pupae and used within 24 h of
eclosion. Mated females were of unknown ages and were collected as they
crawled from the open top of culture vials containing numerous males.
Males were of unknown ages and experience and were collected directly from
the cultures.
Melittobia females are polymorphic (Schmieder 1933, Freeman and
Ittyeipe 1982). Because the forms differ in some aspects of their behavior
(Freeman and Ittyeipe 1982), each was used separately, and forms were
never intermixed. The morph used (macropterous = type form, brachyp-
terous = second form) is indicated for each experiment.
Experimental Apparatus. Initial experiments used an airflow olfacto-
meter described by Vet et al. (1983) for studies of other small parasitoid
wasps. However, absence of air movement and the relatively small space
characteristic of the natural habitat of Melittobia (e.g. the host cocoon),
suggested that another design might provide a more realistic bioassay.
Therefore, for the bioassay experiments, a small plastic container was
modified to serve as an experimental arena (Fig. 1). Gelatin capsules
(choices) were inserted into holes drilled at 4 equidistant points around
the perimeter of the container. One half of each capsule, with an end snipped
off to allow entry into the plastic container, was permanently affixed to it
with paraffin wax. The other half was removable. A fine mesh screen (4
sq/mm), through which females could pass, was attached to the inside
Fig. 1. Experimental apparatus used in experiments on Melittobia at-
tractants.
280
Gonzalez et al.: Melittobia pheromone
281
of the chamber wall by melting the plastic and embedding the screen. A tube
pushed through a hole drilled into the center of the container lid allowed
introduction of experimental subjects into the container's main chamber.
General Methodology. At the start of each trial, various combinations of
Melittobia wasps (see below) were placed in the capsules. Groups of 14-25
females were introduced into the main chamber. Once each hour for the
next 4 h, the number of females present in each choice capsule was record-
ed. Counts were terminated after 4 h because preliminary observations
indicated that by this time all females could be presumed to have had the
opportunity to mate.
To control for the possibility of odor contamination, new capsule halves
were used to hold the choices for each trial. To avoid possible effects of
light, all trials were run in total darkness and observations were made using
a flashlight with a red filter. To remove possible bias due to positional
effects, the apparatus was rotated each time data were collected. In repli-
cate trials, the choices were randomly arranged in the capsules. Experi-
ments were run at room temperature and set at different hours between De-
cember 1983 and July 1984.
Statistical Analysis. To test the assumption that experimental replicates
came from populations having identical behaviors, a heterogeneity Chi-
equare analysis (Zar 1974) was performed on the replicated trials of each
experiment. In all cases, the null hypothesis was not rejected (a = 0.05);
therefore the data were considered to be homogeneous and subsequent
statistical analyses were performed on the pooled results for each experi-
ment. Contingency and goodness-of-fit Chi-square tests were used in the
data analyses.
Experimental Protocol. The following questions were experimentally ad-
dressed:
1. Are virgin females attracted to other Melittobia or are they dis-
persing at random? Experiment 1 was run using only empty capsules
as the 4 choices to determine whether females might end up in the
capsules simply as a result of their efforts to disperse from the
chamber and whether any features of the apparatus itself might
influence wasp dispersion.
2. Are virgin females attracted more to newly closed males than to
dead or living females or dead males? If so, is this attraction
chemically cued? Experiment 2 offered virgin females choices be-
tween living males, living mated females of the same morph, and
males and mated females which had been freshly killed by mashing
them with the blunt end of a camel's hair brush handle.
3. Is the presumed attractant a rapidly decaying volatile chemical? In
experiment 3, virgin females were offered live males, freshly mashed
males, and "old" and "new" dead but intact males. "Old" dead
males, taken from defunct cultures, had been dead for at least 5
days. "New" dead males were taken alive from their culture and
quickly killed by close range (<2 cm) exposure to heat from a 40 watt
incandescent bulb for 1 min. This treatment presumably left the
body juices intact, in contrast to the mashed males whose body
juices were exposed.
4. Is the attractive substance a true sex pheromone, differentially at-
tractive to virgin females? The same choices offered in experiment 3
282 Florida Entomologist 68 (2) June, 1985
were repeated in experiment 4, but the test females were known to
have been previously mated. Females become refractory after mating
(Matthews 1975). Therefore, if the attractive substance were truly
a sex pheromone rather than a generalized aggregant/arrestant, then
mated females should be much less responsive to it than virgin
females would be.
5. Finally, what body region is the source of the attractive substance?
For experiment 5, we carefully dismembered live males and placed
each body portion (head, thorax, and abdomen) into different choice
capsules, with the 4th capsule left empty as a control.
RESULTS
From observations under red light, it was apparent that wasp distribu-
tion in the chamber and choice capsules had reached an equilibrium by the
end of the first hour. Either females that had made their choices remained
mostly stationary, or movements in and out of the choice capsules canceled
out each other. Although data were recorded over a 4 h period, there were
no discernable changes in distributions and census data in hours 2, 3, and 4,
and the data were considered equivalent. Because over time the females'
behavior appeared increasingly to switch to a dispersal mode, thereby
possibly confounding the results, subsequent analysis generally used only
counts made at the end of the first hour. However, analyses using means
of the 4 hourly counts produced the same levels of statistical significance
as did those based on the first hour counts, so in some cases data are pre-
sented as means of the 4 hourly censuses.
Experiment 1. Virgin Melittobia females were not attracted to empty choice
capsules. Only once was a female recorded in a choice capsule at the hourly
census. This distribution was in strong contrast to the experimental results
discussed below, where in every case except experiments 4 and 5, more than
half of the introduced females were recorded from 1 or more of the 4
choice capsules. Therefore we conclude that females arrive in the capsules
as a result of active choice, not random dispersal.
Experiment 2. From Table 1, it is apparent that virgin females offered a
TABLE 1. VIRGIN FEMALE Melittobia ATTRACTION TO CONSPECIFIC MALES
AND FEMALES, DEAD AND ALIVE.
Wasp in Capsule:
Female Species Male Female Sample
and Form Dead Alive Dead Alive Size2
australica
brachypterous 25.75+ 0.961 22.00 2.16 0.50 + 0.58 0.25 + 0.50 70
macropterous 25.25 + 5.25 6.50 1.29 1.50 1.00 2.50 0.58 80
femorata
brachypterous 21.25 0.96 8.50+1.73 0.75+0.96 0.75-0.50 68
macropterous 20.50 5.97 4.75 1.26 2.00- 0.82 1.25 1.26 50
'Mean (+SD) of 4 counts taken 1, 2, 3, and 4 h after trial initiation.
2Includes females remaining in central chamber. All female wasp distributions were
significantly different (P<.001) from random.
Gonzalez et al.: Melittobia pheromone 283
choice between conspecific males and females, both alive and dead, clearly
preferred those capsules containing males (P<.001). Both morphs be-
haved in the same manner in this regard (australica P<.25; femorata P
<.75). Similarly, there was no difference between the 2 species. Finally, al-
though virgin females taken as a whole appeared to prefer dead to living
males, the difference was not statistically significant.
Experiment 3. The attraction of virgin females to males in various con-
ditions is shown in Fig. 2 and 3. "Old" dead intact males were not attractive
to virgin females of either species. However, somewhat surprisingly, living
males were the most preferred choice only for brachypterous australica fe-
males. Significantly more brachypterous females than macropterous females
of M. australica preferred living males (P<.001), the only experiment for
which the 2 morphs of a species did not behave in a consistent fashion. Both
femorata morphs, like the macropterous australica form, showed the strong-
est preference for dead males (either intact "new" or mashed).
Experiment 4. Mated females of both species were almost indifferent to
males offered in choice capsules, regardless of male condition. The majority
of the released females remained in the chamber, either wandering or
resting motionless, especially at the top.
Experiment 5. Responses of virgin females of both species to various body
regions of a freshly trisected male revealed a decided preference for the
abdominal section (Table 2). The thorax was approximately one-third
as attractive as the abdomen; the head was totally non-attractive. The
difference in attractiveness between the thorax and abdomen was statistical-
ly significant (P<.001). Neither the morphs nor the species showed any
statistically significant differences in body region choice.
r 50
0 MACROPTEROUS FORM, n 103
'J 45
S 45 BRACHYPTEROUS FORM, n : 65
c 40
Z 35
30
r 25
_J 20
Co 10
5
r; 0
LIVING MASHED INTACT INTACT
DEAD "NEWLY" "OLD"
DEAD DEAD
CONDITION OF MALE
Fig. 2. Attraction of virgin M. australica females to conspecific males in
various conditions,
Florida Entomologist 68 (2)
June, 1985
* MACROPTEROUS FORM, n 87
% BRACHYPTEROUS FORM, n : 50
LIVING
MASHED INTACT
DEAD "NEWLY"
DEAD
CONDITION OF MALE
Fig. 3. Attraction of virgin M. femorata females
various conditions.
284
-c
hi
a-
C:)
CD
-J
Cu
U-
U-
0
C3
CD
C-
Clu
Li
UJ
to conspecific males in
DISCUSSION
Both the nearly complete absence of female attraction to "old" intact
dead males and females' decided preferences for males in the other 3 con-
ditions (experiment 3) provide substantial evidence that volatile chemical
cues mediate this response. The strength of the response to the mashed male
(particularly for macropterous australica females) suggests that the pro-
cess of mashing allows the attractant odor to be released in greater quantity.
The pheromone probably originates from the abdominal region. In experi-
ment 5, abdomens were 3x as attractive as thoraces, and heads were
TABLE 2. VIRGIN FEMALE Melittobia ATTRACTION TO BODY REGIONS OF
CONSPECIFIC MALES.
Female Species Male Body Part' Sample
and Form Thorax Abdomen Size
australica
brachypterous 4.00 1.832 11.25 1.50 40
macropterous 4.75 0.50 20.00 1.63 100
femorata
brachypterous 9.00 1.41 24.75 4.03 108
macropterous 7.00 1.41 21.00 3.37 105
'Four choices were given (male head, thorax, and abdomen, and an empty capsule-
"control"-. No females responded to capsules containing either male heads, or the
control.
ZMean (SD) of 4 counts taken 1, 2, 3, and 4 h after trial initiation.
50
45
40
35
30 -
25
20
15
10
5
0
INTACT
"OLD"
DEAD
Gonzalez et al.: Melittobia pheromone 285
totally non-attractive. We suspect that the presumed gland may be situated
near the base of the abdomen; our relatively crude dissection techniques
could have resulted in some contamination of the thorax portions. Histo-
logical studies are needed to resolve the question. However, courting males
typically adopt a raised-wing "calling" posture (van den Assem et al. 1982),
which may behaviorally corroborate the gland position.
Results of experiment 4 seem to justify calling the attractive substance
a true sex pheromone, since mated females were quite unresponsive to males,
regardless of condition. These results contrast strikingly to those of ex-
periment 2, in which virgin females were used.
Because mating occurs before dispersal, and generally does not differ
for brachypterous and macropterous forms of a Melittobia species, we
would have predicted that the behavioral response of the two morphs of
each species to the choices offered would be consistent. Only the brachyp-
terous morph of M. australica in experiment 3 differed from the others.
Although M. australica's different responses may reflect differing underlying
behavioral propensities, in the absence of hard data we prefer to label
them "anomalous".
Male-produced olfactory cues are rare throughout the parasitic Hymenop-
tera (Gordh and DeBach 1978). Among the Melittobia, however, blind,
flightless males appear to use a volatile pheromone to attract newly closed
virgin females. Such a system appears to be highly adaptive. Melittobia live
in the closed confines of the host cocoon, from which the females disperse
immediately after mating and within which the poorly mobile males must
compete with their brothers for copulations. Sex ratios are character-
istically strongly female-biased (ca. 95:5), and the relatively uncommon
males are often aggressive and cannibalistic toward other males (Dahms
1984a, Matthews 1975). The manner in which the blind males recognizes
others of their own sex has not been investigated, but the recognition is
probably chemically cued and could involve the sex pheromone.
Females of both Melittobia utilize the same host and displayed a similar
response to male odor in our experiments. However, they belong to quite
different species groups in the genus (Dahms 1984b), and their courtship
patterns differ in several respects (Gonzalez and Matthews, unpublished ob-
servations). Since sexual communication systems should be expected to
maintain the integrity of each species' own communication channel, the
question of the existence or extent of cross-attractancy is an interesting one
which will be considered elsewhere (Matthews et al. 1985).
REFERENCES CITED
ASSEM, J. VAN DEN, H. A. J. IN DEN BOSCH, AND E. PROOY. 1982. Melitto-
bia courtship behaviour: a comparative study of the evolution of a
display. Netherlands J. Zool. 32: 427-471.
DAHMS, E. C. 1984a. A review of the biology of species in the genus
Melittobia (Hymenoptera: Eulophidae) with interpretations and
additions using observations on Melittobia australica. Mem. Qld. Mus.
21: 337-360.
--- 1984b. Revision of the genus Melittobia (Chalcidoidea: Eulophidae)
with the description of seven new species. Mem. Qld. Mus. 21: 271-
336.
EVANS, D. A., AND R. W. MATTHEWS. 1976. Comparative courtship behavior
in two species of the parasitic chalcid wasp Melittobia. Anim. Behav.
Florida Entomologist 68 (2)
24: 46-51.
GORDH, G., AND P. DEBACH. 1978. Courtship behavior in the Aphytis
lignanensis group, its potential usefulness in taxonomy, and a review
of sexual behavior in the parasitic Hymenoptera (Chalcidoidea:
Aphelinidae). Hilgardia 46: 37-75.
FREEMAN, B. E., AND K. ITTYEIPE. 1982. Morph determination in Melittobia,
a eulophid wasp. Ecol. Ent. 7: 355-363.
HERMANN, L. D. 1971. The mating behavior of Melittobia chalybii (Hymeno-
ptera:Eulophidae). M.S. thesis. University of Georgia. 52 pp.
-- H. R. HERMANN, AND R. W. MATTHEWS. 1974. A possible calling
pheromone in Melittobia chalybii (Hymenoptera:Eulophidae). J.
Georgia Ent. Soc. 9(1): 17.
MATTHEWS, R. W. 1975. Courtship in parasitic wasps. Pages 66-86 in
P. W. Price, ed. Evolutionary Strategies of Parasitic Insects and
Mites. Plenum Publ. Co., New York.
-- J. YUKAWA, AND J. M. GONZALEZ. 1985. Sex pheromones in male
Melittobia parasitic wasps: female response to conspecific and con-
generic males of 3 species. J. Ethology 3: (in press).
SCHMIEDER, R. G. 1933. The polymorphic forms of Melittobia chalybii
Ashmead and the determining factors involved in their production
(Hymenoptera, Chalcidoidea, Eulophidae). Biol. Bull. 65: 338-354.
VET, L. E. M., J. C. VAN LENTEREN, M. HEYMANS, AND E. MEELIS. 1983. An
airflow olfactometer for measuring olfactory responses of hymenop-
terous parasitoids and other small insects. Physiol. Ent. 8: 97-106.
ZAR, J. H. 1974. Biostatistical Analysis. Prentice-Hall, Inc., Englewood
Cliffs, New Jersey.
EFFECT OF GAMMA-RADIATED MALES ON
EGG PRODUCTION IN ACARUS SIRO
EWA SZLENDAK AND JAN BOCZEK
Department of Applied Entomology
Agricultural University of Warsaw
Nowoursynowska 166,
POLAND
AND
WILLIAM BRUCE AND ROBERT DAVIS
Stored-Product Insects Research and Development Laboratory
Agricultural Research Service, USDA
Savannah, Georgia 31403, U.S.A.
ABSTRACT
Mating of unirradiated Acarus siro L. females with normal and gamma
irradiated males was studied. Females usually laid eggs throughout their
life span if they were mated at least once a week with normal males. Fe-
males paired with treated males contained spermatophores but did not lay
any eggs. Previously mated fertile females of A. siro subsequently mated
with irradiated, sterilized males ceased egg-laying during the next 1-2
weeks. There was no significant difference when compared to the untreated
control in the number of eggs laid when females were mated for one week
with irradiated males and then with normal males. Weekly alternation of
286
June, 1985
V o
Szlendak et al.: Gamma-Radiated Acarus siro
287
mating with irradiated and normal males reduced significantly the number
of eggs laid by the females and significantly reduced their longevity. Be-
cause this mite species mates many times during its life span, it is doubtful
that it could be eradicated solely by the introduction of sterile males into
a natural population. However, the presence of such males would decrease
the number of eggs laid by normal females and it would lead to the decrease
in the number of offspring in the next generation.
RESUME
Se estudi6 el apareamiento de hembras de Acarus siro L. no-irradiadas
con normales y de machos irradiados con rayos gamma. Las hembras usual-
mente depositan los huevos a trav6s de su ciclo vida si se aparean con
fachos normales por lo menos una vez por semana. Hembras apareadas con
machos expuestos contenian espermatoforas, pero no pusieron huevos. Pre-
viamente apareadas hembras fertiles de A. siro y apareadas subsequente-
mente con machos irradiados y esterilizados, cesaron de poner huevos durante
las siguientes 1-2 semanas. No hubo diferencia en el nfmero de huevos
puestos entire el testigo y las hembras apareadas por una semana con machos
irradiados y despu6s con machos normales. Alternando semanalmente
apareamientos con machos irradiados y normales, redujo significativamente
el nimero de huevos puestos por hembras y su logevidad. Debido a que esta
especie de acaro se aparea muchas veces durante su vida, es dudoso que
pueda ser erradicado en una poblaci6n natural solamente con la introducci6n
de machos esteriles. Sin embargo la presencia de tales machos disminuiria
el ndmero de huevos puestos por hembras normales, lo cual traeria una dis-
minuci6n en el nfmero de la prole de la generaci6n siguiente.
The grain mite, Acarus siro L., is an important cosmopolitan pest of grain
and grain products. Studies on the radiosensitivity of the various stages of
this species and the effects of ionizing radiation on its reproductive potential
determined that ionizing radiation can kill, reduce fertility and/or sterilize
this species (Burkholder et al. 1966, Brown and Davis 1969 and 1972, Davis
1972, and Hemenway and Davis 1972). This was considered to be a result
of polyandry that allowed residual fertile males to neutralize any effect
of the sterile males. The aim of this work was to check the effect of sterile
males on the reproduction of the population.
This paper reports the results of a study to determine if sterilization
of a portion of the grain-mite male population offers any potential as a
control mechanism.
MATERIALS AND METHODS
All grain mites used in this study were from stock colonies at the Agri-
cultural University of Warsaw, Poland. These colonies are maintained on
wheat germ at 25 IC and 89% RH. All tests were conducted under these
same environmental conditions. Inert deutonymphs were selected from stock
colonies and placed into individual glass cages with wheat germ as food.
The next day, the adults that emerged were sexed and irradiated with 60
krad in a 60 Co irradiator at 128 rad/sec. The selection of 60 krad was made
because Brown and Davis (1969) found 50 krad to be an effective sterilizing
dose for males for population control. Virgin adults were then paired in the
following combinations:
Florida Entomologist 68 (2)
June, 1985
A-untreated (U) female with U male (control);
B-U female with U male together for 7 days, then male discarded;
C-U female with U male together for 7 days, male then replaced with
U male;
D-U female with treated (T) male;
E-U female with T male for 7 days, male then discarded;
F-U female with U male for 7 days, male then discarded and replaced
with T male;
G-U female with T made for 7 days, then male discarded and replaced
with U male;
H-U female paired alternately with a T and a U male every other
week;
I-U female paired alternately with a U and a T male every other week.
In pairing combinations H and I, all mites in each set of pairings were
the same age. Fecundity was determined by counting and discarding eggs
each week. At least twenty-two pairings were used in each combination.
RESULTS AND DISCUSSION
Female grain mites in mating conditions B lived the longest (Table 1),
but not significantly longer than those in conditions A, D, E, F, and G. Mites
subjected to mating conditions H and I had a significantly shorter mean
lifetime than those in all other test conditions. This situation may be a
result of repeated copulation with the males (harassment) as noted by
Boczek (1957). The means of egg production for conditions A, B, and C
were not significantly different. Males sterilized by irradiation transfer
spermatophores when mating (unpublished results), but the females never
were observed to lay eggs (Table 1D and E). In earlier tests, mites treated
with the same dose laid singular eggs.
Females which were mated with untreated males at least once a week (A
and C) usually laid eggs continuously throughout their lives (Table 2).
Boczek (1957) found that female grain mites had their maximum egg pro-
duction with one mating per week; with mating conditions B and F, sig-
TABLE 1. LONGEVITY AND OVIPOSITION OF FEMALE Acarus siro AS AFFECTED
BY NINE MATING CONDITIONS. RESULTS ARE MEANS RESULTING
FROM 22-35 MALE/FEMALE PAIRINGS.1
Longevity Oviposition
Mating Condition (weeks) (# of eggs)
A 4.8 a, b 119.3 a
B 5.6 a 97.7 a,b
C 4.4 b, c 122.0 a
D 5.1 a,b _2
E 5.2 a,b -2
F 5.2 a,b 64.9 d
G 4.8 a, b 82.6 b, c
H 3.7 c 40.5 d
I 3.7 c 73.9 b,
'Means followed with the same superscript are not significantly different at the 5% level.
2No eggs were laid; not included in analysis.
288
Szlendak et al.: Gamma-Radiated Acarus siro
289
TABLE 2. MEAN NUMBER OF EGGS LAID PER WEEK BY Acarus siro AS A RESULT
OF NINE DIFFERENT MATING CONDITIONS.
Condition
Week A B C F G H I
1 45.2 a 56.1 a 49.5 a 46.3 a 0.0 c 0.0 c 45.6 a
2 33.0 a,b 40.5 b 30.0 a,b 16.4 b 46.6 a 25.8 a 9.2 b
3 26.4 a,b,c 1.5 c 23.3 a,b 1.7 b 21.2 b 4.6 b,c 15.8 b
4 10.0 bc 0.4 c 25.3 a,b 0.5 b 22.1 b 18.6 a 3.8 b
5 5.9 e 0.0 C 7.4 b 0.3 b 4.5 c 2.4 c 13.6 b
6 2.5 0.0 3.3 b 0 3.0 b 10.7 b,c 16.8 a 2.7 b
7 2.0 c 0.0 c 5.5 b 0.0 b 2.5 c 0.0 c 0.0 C
8 0.0 c 0.0 c 2.0 b 0.0 b 1.5
9 0.0 c 0.0 b 0.0 C
'Means followed with the same superscript letter within a column are not significantly
different at the 5% level.
nificant reductions in egg production occurred after removal of the untreated
male. In 1977, Griffiths and Boczek observed in this mite that several matings
can occur within one week resulting in the placement of several spermato-
phores in the female spermatheca. It appears from conditions B, H, and I
that such a surplus of spermatophores will only provide viable sperm for
slightly more than one week at a near maximum rate of egg laying.
The overall fecundity of the females in test condition G was little
affected by an initial pairing with a treated male when total number of
eggs is compared with test condition A (control). The introduction alter-
natively of treated and untreated males on a weekly schedule (test con-
ditions H and I) caused increases and decreases in egg laying that, in most
instances, were significant and were related to the kind of male used
(Table 2).
The use of introduced sterile males to control a population of the grain
mite would be questionable. The level of control would be dependent upon
the ratio of sterile to normal males achieved within the population and the
duration this ratio was maintained. Brown and Davis (1969) found that
sublethal doses of gamma radiation could be used to cause a distinct re-
duction in grain mite populations, but eradication was questioned.
ACKNOWLEDGEMENT
This study was supported by grants from the USDA and the Marie
Sklodowska-Curie Fund (PL-ARS-98 and 104).
REFERENCES CITED
BOCZEK, J. 1957. Grain mite (Tyroglyphus farinae (L.) (Acarina). Roczn.
Nauk. Roln., Warsaw. 75-A-4: 559-644.
BROWN, G. A., AND R. DAVIS. 1969. Effects of introduced irradiated male
grain mites on population development. J. Econ. Entomol. 62: 767-71.
BROWN, G. A., AND R. DAVIS. 1972. Sensitivity of grain mite eggs to gamma
radiation as influenced by dose rate and treatment age. Ibid. 65: 1619-
21.
BURKHOLDER, W. E., E. W. TILTON, AND R. R. COGBURN. 1966. Effects of
290 Florida Entomologist 68 (2) June, 1985
gamma radiation on the grain mite, Acarus siro. Ibid. 59: 976-80.
DAVIS, R. 1972. Some effects of relative humidity and gamma radiation on
population development in Acarus siro (Acarina: Acaridae). J.
Georgia Entomol. Soc. 7: 57-63.
GRIFFITHS, D. A., AND J. BOCZEK. 1977. Spermatophores of some acaroid
mites (Astigmata: Acarina). Internat. J. Insect Morphol. Embryol.
6: 231-38.
IGNATOWICZ, S., J. BOCZEK, R. DAVIS, AND W. A. BRUCE. 1983. Utilization of
irradiated sperm from successive mating by the mold mite (Acari:
Acaridae). J. Econ. Entomol. 76: 684-86.
-^- --e c-- -e-- -- --^-- --^-^-- --
FALL ARMYWORM (LEPIDOPTERA: NOCTUIDAE):
FIELD SURVIVAL OF F, LARVAE FROM
PARTIALLY STERILE PARENTS
J. E. CARPENTER, J. R. YOUNG, AND A. N. SPARKS
Insect Biology and Population Management Research Laboratory,
USDA-ARS,
Tifton, GA 31793
ABSTRACT
Fall armyworm, Spodoptera frugiperda (J. E. Smith), larvae from both
irradiated (10 krad) and normal parents were compared for their ability
to survive under field conditions on whorl-stage sweet corn and under
laboratory conditions on a meridic diet. Survival rates for F, larvae from
irradiated and normal parents were similar under laboratory and field con-
ditions. Implications of the use of inherited sterility for the control of fall
armyworm are discussed.
RESUME
Larvas del cogollero, Spodoptera frugiperda (J. E. Smith), de padres
irradiados (10 krad), fueron comparadas por la habilidad de sobrevivir
bajo condiciones de campo en la etapa verticular del maiz dulce y bajo
condiciones de laboratorio en una dieta meridica. Grados de sobreviviencia
de larvas F, de padres irradiados y de padres normales fueron similares
bajo condiciones de laboratorio y de campo. Se discuten las implicaciones
del uso de esterilidad hereditaria para el control del cogollero.
The potential of inherited sterility as a component of area-wide man-
agement of the fall armyworm (FAW), Spodoptera frugiperda (J. E.
Smith), was suggested by Knipling (1980) and later demonstrated in labora-
tory studies by Carpenter et al. (1983). These researchers used a theoretical
model to aid in understanding the potential effect of persistent genetic sup-
pressive action through several successive generations and concluded that
males irradiated with a substerilizing dose (10 krad) would be 6.7 times
more effective in suppressing FAW reproduction than completely sterile
males. One assumption of the theoretical model was that the magnitude of
deleterious effects during the growth and development of the F, generation
Carpenter et al.: Armyworm F, Sterility
would be the same under field conditions as observed in the laboratory. We
designed a study to test this assumption by comparing laboratory and field
survival of larvae from normal and irradiated parents.
MATERIALS AND METHODS
The FAW used in this study were from a five-generation-old colony
that was started from a field collection of late-instar larvae. All FAW were
reared in 30 ml plastic cups (each cup infested with three Ist-instar larvae)
containing meridic diet (Burton 1967). The photoperiod regime was 14 h
light and 10 h dark with temperatures of 29 1 and 24 10C, respective-
ly. Relative humidity was maintained at ca. 70%. All irradiation was done
with a well-type 60CO source delivering 1.0 krad/min.
Male and female adults (1 to 12 h old) were treated (T) with 10 krad of
gamma radiation. These irradiated adults were paired together (T 9 xT )
and with normal (N) adults (T xN N xT ). A N xN cross was
the control. In each of these four crosses, five pairs of moths were placed
in each of ten 3.8 liter containers for mating and oviposition. Randomly
selected egg masses were removed from the containers for laboratory and
field experiments. Laboratory mortality studies were conducted according to
the methods described by Carpenter et al. (1983).
Field studies were conducted on the Southern Grain Insects Research
Laboratory experimental farm near Tifton, Ga. In 1982, the study area was
planted with 'Silver Queen' sweet corn in rows 0.32 m apart. Each plot
was 18 rows wide and 15.3 m long. Centered within this plot was a 12-row x
9.2 m area designated as the buffer zone. Outside the buffer zone to the
boundary of the plot was designated as the control subplot. Centered within
the buffer zone was a 6-row x 6.1 m area designated as the treated sub-
plot. Thus, each treated subplot was surrounded by a buffer zone, and each
buffer zone was surrounded by a control subplot. This design was intended
to detect any movement of larvae from the treated subplots into the buffer
zones. If larvae dispersed in this manner, the buffer zones would sustain
more damage from larval feeding than the surrounding control subplots. The
plots were placed in a randomized complete block design and replicated 9
times.
On 4 May 1982, sufficient quantities of egg masses were placed at random
in the late whorl of plants within each treated subplot to yield 1000 first-
instar larvae per cross per subplot. Laboratory data were used to determine
differential egg hatch among the crosses. The control and treated subplots
and the buffer zone of each plot were observed (50 plants/subplot) for recent
larval feeding before the plants were hand-infested on 4 May and after-
wards on 13 and 19 May. Since many larvae moved from the whorl to the
ears during development, all corn ears and stalks within the plots were
dissected on 21 May and the mature larvae found were recorded.
Experimental plots in 1983 were planted with Silver Queen sweet corn
in rows 0.48 m apart. Each plot was 18 rows wide and 12.2 m long. Centered
within this plot was a 6-row x 6.1 m area designated as the treated subplot.
The area outside the treated subplot to the plot boundary served as the
control subplot. Plots were arranged in a randomized complete block design
and replicated seven times. Within each subplot, 30 plants were selected at
random and flagged. Each flagged plant was hand-infested with ca. 70 eggs
from the appropriate cross. Plants were infested at late whorl stage on 20
291
Florida Entomologist 68(2)
June, 1985
May. The flagged plants in control and treated subplots were inspected on
19 and 30 May and on 2 and 8 June for recent larval feeding. On 8 June,
all flagged plants were dissected and mature FAW larvae were counted,
placed in 30 ml plastic cups containing meridic diet, and allowed to pupate.
The number of parasitized larvae and viable FAW adults produced from
the collected larvae was also recorded.
RESULTS
The pretreatment surveys during 1982 and 1983 indicated that the experi-
mental plots were free from a natural FAW infestation. However, many of
the corn plants were damaged due to larval feeding caused predominantly
by Heliothis zea (Boddie) and Ostrinia nubilalis (Hfibner).
The data (Table 1) indicate that FAW larvae did not disperse into the
buffer zones since there were no significant differences between the number
of plants damaged in the buffer zones and control subplots. Larval dispersal
did occur within the treated subplots but was usually limited to a maximum
of ca. 1.5 m along the row. On 13 May, 1982, significantly more plants
were damaged in the treated subplots of NxN and NxT than in the other
subplots. This trend continued on 19 May, also, to include the treated sub-
plots of TxN. These data indicated that a buffer zone was not needed;
therefore, the experimental plots were modified in 1983.
Field survival of larvae from the different parental crosses is presented
in Table 2. By 13 May, a trend was established with significantly more
plants damaged by larvae of the NxN cross than the TxT cross. The same
relationship among the crosses was evidenced by the data collected on 19
May, by which time larvae from crosses involving normal females damaged
significantly more plants than larvae from crosses with treated females. The
number of mature larvae collected from the treated subplots also demon-
strated this relationship since crosses involving normal females produced
significantly more mature larvae than crosses with treated females.
The trend for larval damage among the crosses in 1983 was similar to
that in 1982 with NxN larvae in most instances damaging the most plants
(Table 3). However, in 1983 NxT was not different from the TxN or NxN
but was significantly different from TxT. Considering the 1982 data, the
number of mature larvae collected from treated subplots in 1983 differs from
TABLE 1. FEEDING AND DISPERSAL OF FAW LARVAE FROM NORMAL AND IR-
RADIATED PARENTS.1
R number of plants with visible damage due to larval feeding2.3,4
13 May 1982 19 May 1982
Plot area NxN NxT TxN TxT NxN NxT TxN TxT
Treated 12.8 a 14.8 a 10.6 a 8.8 a 25.5 a 22.8 a 15.0 a 13.9 a
Buffer 8.8 b 7.6 b 8.5 a 7.9 a 12.2 b 11.3 b 11.8 b 10.7 b
Control 7.6 b 8.2 b 8.5 a 9.0 a 10.3 b 12.4 b 11.8 b 11.9 ab
'Whorl-stage corn infested with egg masses 4 May 1982.
2n = 50.
3N = normal, T = treated (10 krad), female listed first.
4Means followed by the same letter in each column are not significantly different at 5%
level, by Duncan's multiple range test.
292
Carpenter et al.: Armyworm F, Sterility
293
TABLE 2. COMPARISON OF FIELD SURVIVAL BETWEEN FAW LARVAE FROM
NORMAL AND IRRADIATED PARENTS, TIFTON, GA, 1982.1
R % plants damaged due no. mature larvae
P, crosses to treatments collected from
( x S )2 13 May 1982 19 May 1982 treated subplots
NxN 11.8 a 30.4 a 5.0 a
NxT 8.8 ab 20.8 a 4.3 a
TxN 5.4 ab 6.8 b 1.3 b
TxT 2.4 b 5.2 b 1.6 b
'Means followed by the same letter in each column are not significantly different at 5%
level, by Duncan's multiple range test.
2N = normal, T = treated (10 krad).
the number expected. All of the crosses involving treated insects produced
more larvae than anticipated; however, only a few of these larvae completed
their development to the adult stage. Much of the observed mortality from
the mature larval stage to the adult stage was the result of parasitization
by Ophion sp. (Table 3).
The comparison of field and laboratory survival of FAW larvae is pre-
sented in Table 4. In 1982, comparisons were given only for the larval
stages. The greatest deviation between larval survival in the laboratory and
in the field occurred with the TxN cross. The laboratory and field survival
of larvae from other crosses was similar. In 1983, comparisons are given for
the entire development of the F1 (egg-adult). Again, laboratory and field
survival of larvae from cross involving treated insects was similar.
An estimated rate of increase from P, to F, generation for FAW reared
in the field was calculated from our data (Table 5). In making these calcu-
lations, FAW females were assumed to produce an average of 1000 eggs
during their lifetime (Pencoe and Martin 1982, Lynch 1984). In 1982, the
NxN cross suffered a 99.5% mortality rate but still produced a 2.5-fold in-
crease during that generation. It must be emphasized that only data from
the Pi adult to the F, mature larvae were used for these calculations. Data
from the P1 adult to the F1 adult were used in the calculations for 1983. In
1983, the estimated rate of population increase resulting from each cross
was less than onefold, indicating that all of the crosses would experience
a decline in their population levels under the tested rearing conditions. The
estimated rate of population increase from TxT (0.07 x) was especially low,
suggesting that under these field conditions little reproduction is possible
when both parents have been irradiated with 10 krad.
DISCUSSION
Laboratory studies conducted by Carpenter et al. (1983) suggested that
FAW populations may be controlled by releasing moths irradiated with
substerilizing doses of gamma radiation. Large-scale field releases of the
irradiated moths are needed to evaluate fully this control method. An under-
standing of the survival and competitiveness of the irradiated moths and
their progeny under field conditions is a prerequisite to a large-scale release
program. It is especially important to have this information through the
Florida Entomologist 68(2)
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Carpenter et al.: Armyworm F, Sterility 295
TABLE 4. COMPARISON OF FIELD AND LABORATORY SURVIVAL OF FAW LARVAE
FROM NORMAL AND IRRADIATED PARENTS.1
% survival in 1982 % survival in 1983
P, crosses (larval stages) (egg-adult)
( x & )2 Laboratory Field Laboratory Field
NxN 100 a 100 a 100 a 100 a
NxT 77 ab 86 a 62 b 62 ab
TxN 59 bc 26 b 37 bc 33 bc
TxT 43 c 32 b 24 c 10 c
IMeans followed by the same letter in each column are not significantly different at 5%
level, by Duncan's multiple range test.
2NxN cross elevated to 100%. N = normal, T = treated (10 krad).
TABLE 5. ESTIMATED RATE OF INCREASE FROM P1 TO FI GENERATION FOR
FAW LARVAE REARED UNDER FIELD CONDITIONS.'
P1 crosses 1982 1983
( 9 x $ )2 P1 adult to F, late instar larvae P, adult to F, adult
NxN 2.50 0.63
NxT 1.87 0.43
TxN 0.36 0.23
TxT 0.36 0.07
'It is assumed that one female produces 1000 eggs and that sex ratios are 1:1.
2N = normal, T treated (10 krad).
first generation (F,) after a release since most of the radiation-induced
deleterious effects are manifested at this time.
The present study was designed to provide environmental stresses
common to field development of larvae so that any interaction between the
different crosses and rearing conditions could be detected. For example,
egg masses were placed on late whorl-stage corn which provided some pro-
tection for the larvae through the third instar. At this time, however, the
tassel emerged and larvae were forced to move to the ear or another whorl-
stage plant to maintain a food source and protection. Other stress factors
included lower rearing temperatures (12.2 to 21.10C) than occurred under
laboratory conditions, rainfall, and exposure to predators, parasitoids, and
pathogens. The effects of these stress factors were great, reducing survival
of the control insects to 0.13-0.5% compared to ca. 50% under laboratory
conditions.
The data from this study did not detect interaction between the type of
parental cross and the rearing condition of the F, larvae. Although actual
survival rates were much lower in the field than in the laboratory, the rela-
tive survival rates among crosses changed very little. These data supported
the model presented by Carpenter et al. (1983), and allowed us to remain
optimistic in considering the potential of inherited sterility for controlling
populations of the FAW.
Florida Entomologist 68(2)
June, 1985
REFERENCES CITED
BURTON, R. L. 1967. Mass rearing the fall armyworm in the laboratory.
USDA, ARS 33-117, 12 pp.
CARPENTER, J. E., J. R. YOUNG, E. F. KNIPLING, AND A. N. SPARKS. 1983. Fall
armyworm (Lepidoptera: Noctuidae): Inheritance of gamma-in-
duced deleterious effects and potential for pest control. J. Econ. En-
tomol. 76: 378-382.
KNIPLING, E. F. 1980. Regional management of the fall armyworm-a
realistic approach? Florida Entomol. 63: 468-480.
LYNCH, ROBERT E. 1984. Effects of 'Coastal' bermudagrass fertilization
levels and age of regrowth on fall armyworm (Lepidoptera: Noctui-
dae:) Larval biology and adult fecundity. J. Econ. Entomol. 77:
948-953.
PENCOE, N. L., AND P. B. MARTIN. 1982. Fall armyworm (Lepidoptera: Noc-
tuidae) larval development and adult fecundity on five grass hosts.
Environ. Entomol. 11: 720-723.
FALL ARMYWORM (LEPIDOPTERA: NOCTUIDAE)
ORIENTATION AND PREFERENCE FOR
SELECTED GRASSES
N. T. CHANG
Department of Entomology and Nematology, University of Florida,
Gainesville, FL 32611
B. R. WISEMAN AND R. E. LYNCH
Insect Biology and Population Management Research Laboratory
USDA-ARS, Tifton, GA 31793
AND
D. H. HABECK
Department of Entomology and Nematology, University of Florida,
Gainesville, FL 32611
ABSTRACT
Fall armyworm, Sodoptera frugiperda (J. E. Smith), orientation and
preference for 'Coastal', Tifton 10, and Tifton 292 bermudagrass (Cynodon
dactylon (L.) Pers.), C-181, and common centipedegrass [Eremochola ophiur-
oides (Munro) Hack.], and zoysiagrass (Zoysia sp.) were studied. A Y-
tube was used to measure chemoreception as a mechanism for orienting fall
armyworm larvae to excised grass tissue. Larvae showed a significant
orientation to the chemical stimuli from all the grasses but showed no prefer-
ence in paired comparisons. Multiple choice preference tests indicated that
the order of preference for the six grasses was: Tifton 10 (highly pre-
ferred) > Coastal bermudagrass > common centipedegrass > C-181 >
Tifton 292 > (non-preferred) zoyriagrass. Dar-age ratings confirmed the
preference of fall armyworm larvae for Tifton 10 as it sustained 50 times
more damage than zoysiagrass. No differences were observed in the host
plant preference between 1st and 3rd-instar larvae.
296
Chang et al.: Fall Armyzworm Grass Preference
297
RESUME
Se estudi6 la orientacion y preferencia del cogollero, Spodoptera Frugi-
perda (J. E. Smith) hacia 'Coastal', Tifton 10, y Tifton 292 hierba-bermuda
[Cynodon dactylon (L.) Pers.], C-181, hierba-centipede com6n [Eremochola
ophiuroides (Munro) Hack], y hierba-zoysia (Zoysia sp.). Se us6 un tubo en
forma de Y para medir la recepci6n quimica como un mecanismo de orienta-
ci6n de larvas del cogollero hacia tejidos cortados de hierba. Las larvas
indicaron significantemente una orientaci6n hacia el estimulo quimico de
todas las hierbas, pero no indicaron preferencia en comparaciones apareadas.
Pruebas de preferencia multiples indicaron que el orden de preferencia hacia
las seis hierbas fue: Tifton 10 (Altamente preferido) > hierba-bermuda
Coastal > hierbacentipede comuin > C-181 > Tifton 292 > (no-preferida)
hierba-zoysia. Evaluaci6n del grado de dafio confirm la preferencia de larvas
del cogollero por Tifton 10, que sostuvo 50 veces mAs dafio que la hierba-
zoysia. No se observ6 preferencia entire plants hospederas del ler. 3er.
estadio.
The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), one
of the most destructive pests in the southeastern and central U. S. (Lugin-
bill 1928), is characterized by high mobility and polyphagy which make it
difficult to manage. It damages not only important food and fiber crops but
often severely damages grasses grown for pasture, silage, turf, or soil
conservation (Kelsheimer et al. 1953). The widespread distribution of these
grasses makes them extremely important in the population dynamics of
the FAW.
Resistance of bermudagrass, Cynodon dactylon (L.) Pers., to the FAW
was first reported by Leuck et al. (1968) in Tifton 292 (P.I. 290884). In
later studies, Leuck and Skinner (1970) found that mortality of FAW
larvae and pupae was higher on Georgia accession No. 239 (P.I. 289931)
than on 'Coastal.' Lynch et al. (1983) confirmed the high level of re-
sistance in Tifton 292 in evaluations of 9 bermudagrass clones, reporting
that the resistance was primarily antibiosis.
Pencoe and Martin (1981, 1982b) investigated FAW development on 15
grasses and sedges. Goosegrass, Eleusine indica (L.), and Coastal bermuda-
grass were found to be the most suitable hosts, while yellow nutsedge,
Cyperus esculentus L., was the least suitable host, as measured by a host-
suitability index. Multiple choice preference tests showed that goosegrass
was most preferred of the grasses offered to 3rd-instar FAW larvae
(Pencoe and Martin 1982a).
Centipedegrass, Eremochola ophiuroides (Munro) Hack., also has been
identified as resistant to the FAW (Wiseman et al. 1982). Both non-
preference and antibiosis mechanisms of resistance were found when centi-
pedegrass was compared with Coastal bermudagrass and carpetgrass,
Axonopus affinis Chase.
Chemical components in plants influence insect behavior in both food find-
ing and food acceptance (Thorsteinson 1960). The chemicals may act as at-
tractants, stimulants, repellents, or deterrents (Dethier et al. 1960) and
influence insect behavior, including the preference or nonpreference mechan-
ism of resistance as defined by Painter (1951). Numerous studies have
been conducted for both chemical and non-chemical bases of food prefer-
ence of lepidopterous larvae (Hedin et al. 1977). However, the FAW has
298 Florida Entomologist 68 (2) June, 1985
been studied less from an insect-plant relationship than many other eco-
nomically important insect pests. This lack of information prompted a study
on the FAW orientation and host preference mechanisms on several se-
lected grasses.
MATERIALS AND METHODS
Coastal, Tifton 10, and Tifton 292 (P.I. 290884) bermudagrasses, C-181
and common centipedegrass, and zoysiagrass (Zoysia sp.) were selected for
this study. Plants of each grass were obtained from pure stands from the
field and were subsequently maintained in a greenhouse for laboratory evalu-
ations. FAW larvae used in the evaluation were obtained from a laboratory
colony maintained at the Insect Biology and Population Management Re-
search Laboratory (USDA-ARS, Tifton, GA) (Perkins 1979).
FAW Orientation: Orientation of FAW larvae to grass food sources was
evaluated in an olfactometer constructed from two plastic rearing cups
(4-cm diam, 4.5 cm high) connected with a 10-cm "Y-shaped" tube. Grass
clippings (4 g/sample) were placed in one or both of the rearing cups and
the cups were capped. Twenty neonate FAW larvae were then placed in
the entrance of the "Y-shaped" tube with a camel-hair brush after which
the tube was sealed with a cork. The olfactometer was covered with dark
paper to avoid phototactic influences on larval orientation. The number of
larvae reaching each rearing cup after 3 h was noted. Orientation com-
parisons included larval response to each individual grass vs. an empty
cup and a one-on-one comparison of all grasses. Two replications with 5
olfactometers per replication of each comparison were conducted. Differ-
ences within each comparison were expressed in % FAW orienting to the
respective stimuli. Data were evaluated with a t-test for paired com-
parisons.
Preference Tests: Two preference tests examined the responses of neo-
nate FAW larvae to the 6 grasses. In the first test, larvae were presented
a choice of all 6 grasses using the procedure described by Wiseman et al.
(1982). Two leaf blades, each ca. 4.5 cm in length, were placed in a random-
ly paired fashion for each of six replications on moistened filter paper in
the bottom of individual plastic dishes (25-cm diam.) prior to placing 25
neonate FAW into the center of the dish. Data were expressed as percent-
age of larvae on each grass.
The 2nd test with neonate larvae was conducted to present the larvae with
a choice of only 2 of the 6 grasses in each comparison. Two leaf blades of
each of 2 selected grasses were placed opposite each other in a 2.5-cm deep
plastic feeding chamber 8 cm in diam. Five neonate FAW larvae were
then placed in the center of each dish and sealed with a lid. Twenty-four
replications with one dish per replication were used.
A 3rd test was conducted to examine the preference of older FAW
larvae for the 6 grasses. As in the first test, 25-cm diam. dishes were used
in the evaluation and procedures were identical with the exception that
10 leaves of each grass were placed randomly in the 6 equal sections
marked on the filter paper. Then fifteen 3rd-instar larvae were placed in
the center of each dish for 4 replications with 6 dishes per replication.
Dishes in all 3 preference tests were sealed, covered with dark paper
to exclude light influence, and placed in an incubator operated at 26.7
2C and 70 5% RH. The number of larvae on or under each grass
Chang et al.: Fall Armyworm Grass Preference 299
section was recorded after 12, 24, 36, and 48 h of infestation. Leaf damage
was rated after 48 h on a 0-9 scale, where 0 = no damage and 9 = leaf
totally consumed. The preference ratio was obtained by calculating the
mean percentage of larvae on each grass at each observation. The data from
all preference tests were transformed (arcsin V1%) and subjected to an
analysis of variance. The means were separated by Duncan's multiple
range test.
RESULTS AND DISCUSSION
FAW Orientation: In all 6 tests, when larvae were presented a choice of
a specified grass vs. an empty cup in the olfactometer, FAW orientation
was significantly (P <0.05) toward the grass (Table 1). These data indi-
cate that chemoreception has an important role in host plant location by
neonate FAW larvae.
When FAW larvae were presented a choice of 2 grasses, a significant
(P <0.05) difference in FAW orientation was noted in only 1 of the 15
paired comparisons. FAW larvae oriented toward Coastal bermudagrass
significantly (P <0.05) more often than they oriented toward zoysiagrass.
These results indicate that either (1) the host plants released the same or
similar volatile chemicalss, or (2) they released different volatile chemi-
cals that induced an equivalent response in orienting larval movement
toward the host plants.
Preference Tests: When larvae were presented with a choice of all 6
grasses in the 1st preference test, Tifton 10 and Coastal bermudagrass
were preferred (P <0.05) by FAW neonate larvae over Tifton 292 ber-
mudagrass, C-181 centipedegrass, and zoysiagrass at 24, 36, and 48 h (Table
2). The results were expressed as a mean preference ratio (R % FAW on
specific grass- x % FAW on least preferred grass), which indicates that
Tifton 10 was the most preferred while zoysiagrass was the least preferred.
The mean preference ratios closely paralleled damage ratings for the re-
spective grasses. Tifton 10 bermudagrass sustained significantly (P <0.05)
more damage than any other grass, while zoysiagrass was among the least
damaged (ca. 50-fold less than the damage sustained by Tifton 10).
Results of the paired comparisons of grasses (2nd preference test) con-
firmed the results of the 1st preference test. Tifton 10 bermudagrass was
preferred (Table 3) over all other grasses in a one-on-one comparison.
TABLE 1. ORIENTATION OF NEONATE FALL ARMYWORM LARVAE TOWARD PLANT
MATERIAL VERSUS EMPTY CUPS.1
% FAW (R SE) orienting to LSD
Plant material Grass Empty cup (P = 0.05)
Coastal bermudagrass 81.5 7.6 4.5 2.7 8.65
Common centipedegrass 74.5 14.5 19.0 11.8 20.01
Tifton 10 bermudagrass 76.0 5.8 16.5 6.9 9.63
Tifton 292 bermudagrass 83.5 + 9.2 12.5 8.3 13.32
C-181 centipedegrass 82.0 6.6 6.5 + 3.3 7.87
Zoysiagrass 79.5 8.2 9.5 6.8 11.39
'Data based on 2 replications with 5 observations for each replication.
Florida Entomologist 68 (2)
June, 1985
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Chang et al.: Fall Armyworm Grass Preference
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TABLE 3. DAMAGE RATINGS AND PREFERENCE RESPONSES OF NEONATE FALL
ARMYWORM LARVAE TO PAIRED COMPARISONS OF SELECTED GRASSES.1
Mean % FAW larvae on host plant
Grass Tifton 10 Coastal Centipede C-181 Zoysia
Coastal 54.8 a -
21.9 b -
Centipede 38.5 a 44.6 a -
22.8 b 13.6 b -
C-181 46.6 a 47.3 a 30.9 a -
6.6 b 11.6 b 17.1 b -
Zoysia 29.6 a 28.3 a 39.1 a 43.0 a -
4.8 b 8.9 b 2.5 b 5.0 b -
Tifton 292 47.6 a 51.2 a 36.8 a 40.0 a 31.5 a
3.8 b 7.0 b 5.0 b 35.1 a 3.3 b
'Means within a column for each comparison not followed by the same letter are sig-
nificantly different (P = 0.05) by Duncan's multiple range test. For each comparison, the
upper mean relates to the grass in the upper column and the lower mean refers to the grass
in the left margin.
Coastal bermudagrass was more preferred and had a significantly higher
damage rating than common centipedegrass, thus confirming results re-
ported by Wiseman et al. (1982). Coastal bermudagrass also was pre-
ferred over C-181 centipedegrass, zoysiagrass, and Tifton 292 bermuda-
grass. Common centipedegrass was preferred over C-181, Tifton 292 ber-
mudagrass, and zoysiagrass. Among the nonpreferred grasses, C-181,
Tifton 292 bermudagrass, and zoysiagrass, zoysiagrass was the least pre-
ferred, again demonstrating the high level of resistance discovered in this
grass species.
Based on damage ratings and larval preference ratios, common centi-
pedegrass was more preferred than C-181, Tifton 292 bermudagrass, or
zoysiagrass. However, there was no significant difference in the damage
rating between C-181 and common centipedegrass. Zoysiagrass was pre-
ferred less than C-181 and Tifton 292 bermudagrass. However, differences
between the damage ratings of the least preferred grasses, such as C-181
centipedegrass (0.9) vs. Tifton 292 bermudagrass (0.5) and Tifton 292
bermudagrass (0.4) vs. zoysiagrass (0.1), were more difficult to deter-
mine since the damages were very negligible. The damage ratings were
not significant and did not reflect feeding differences. Results were also
confounded by high mortality during the tests that compared Tifton 292
bermudagrass and zoysiagrass.
Preferences of 3rd-instar FAW larvae for the various grasses (Table
4) were similar to those exhibited by neonate larvae. Tifton 10 bermuda-
grass was the most highly preferred at 12, 24, and 36 h, had the highest
mean preference ratio, and sustained the most damage of all grasses
examined, while Tifton 292 bermudagrass and zoysiagrass were among the
least preferred. Thus, FAW larval age had little influence on host plant
preference.
In comparing results of all 3 preference tests, the 6 grasses can be ranked
in their order of preference by FAW larvae as follows: Tifton 10 bermuda-
grass is highly preferred; Coastal bermudagrass is moderately preferred;
Florida Entomologist 68 (2)
June, 1985
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Chang et al.: Fall Armyworm Grass Preference
303
common and C-181 centipedegrass are moderately nonpreferred; Tifton
292 bermudagrass and zoysiagrass are highly nonpreferred. Our results
demonstrate that nonpreference, in addition to antibiosis (Lynch et al.
1983), is also a component of the resistance of Tifton 292 bermudagrass to
the FAW.
Earlier studies have shown that Coastal bermudagrass (Leuck and
Skinner 1970) and Tifton 10 bermudagrass are susceptible to FAW feed-
ing, while centipedegrass (Wiseman et al. 1982), zoysiagrass (unpublished),
and Tifton 292 bermudagrass (Leuck et al. 1968, Lynch et al. 1983) are re-
sistant. However, as our studies have indicated, the preference or non-
preference for these grasses as host plants occurred only after FAW larvae
perceived the presence of the grass through chemoreception, moved toward
the grass, and began feeding.
REFERENCES CITED
DETHIER, V. G., L. B. BROWNE, AND C. N. SMITH. 1960. The designation of
chemicals in terms of the responses they elicit from insects. J. Econ.
Ent. 53: 134-136.
HEDIN, P. A., J. N. JENKINS, AND F. G. MAXWELL. 1977. Behavioral and de-
velopmental factors affecting host plant resistance to insects. pp. 231-
275. In P. A. Hedin (ed.), Host plant resistance to pests. ACS Sym-
posium Ser. No. 62. 286 p.
KELSHEIMER, E. G., D. W. JONES, AND E. M. HODGES. 1953. Control of some
insect pests of improved pastures. Florida Agr. Exp. Stn. Circ. S-64:
1-4.
LEUCK, D. B., C. M. TALIAFERRO, G. W. BURTON, R. L. BURTON, AND M. C.
BOWMAN. 1968. Resistance in bermudagrass to the fall armyworm.
J. Econ. Ent. 61: 1321-1322.
LEUCK, D. B., AND J. L. SKINNER. 1970. Resistance in bermudagrass affecting
control of the fall armyworm. J. Econ. Ent. 63: 1981-1982.
LUGINBILL, P. 1928. The fall armyworm. USDA Tech. Bull. 34. 92 p.
LYNCH, R. E., W. G. MONSON, B. R. WISEMAN, AND G. W. BURTON. 1983.
Bermudagrass resistance to the fall armyworm (Lepidoptera: Noc-
tuidae). Environ. Ent. 12: 1837-1840.
PAINTER, R. H. 1951. Insect resistance in crop plants. The MacMillan Co.,
New York. 520 p.
PENCOE, N. L., AND P. B. MARTIN. 1981. Development and reproduction of
fall armyworms on several wild grasses. Environ. Ent. 10: 999-1002.
-- AND 1982a. Grass hosts of fall armyworm larvae: Prefer-
ence and methods of determination. J. Georgia Ent. Soc. 17: 126-132.
AND 1982b. Fall armyworm (Lepidoptera: Noctuidae) larval
development and adult fecundity on five grass hosts. Environ. Ent.
11: 720-723.
PERKINS, W. D. 1979. Laboratory rearing of the fall armyworm. Florida
Ent. 62: 87-91.
THORSTEINSON, A. J. 1960. Host selection in phytophagous insects. Annu.
Rev. Ent. 5: 193-218.
WISEMAN, B. R., R. C. GUELDNER, AND R. E. LYNCH. 1982. Resistance in
common centipedegrass to the fall armyworm. J. Econ. Ent. 75:
245-247.
Florida Entomologist 68 (2)
A NATURAL DECLINE OF PESTIFEROUS
CHIRONOMIDAE (DIPTERA) POPULATIONS FROM
1979 TO 1984 IN AN URBAN AREA OF
CENTRAL FLORIDA
ARSHAD ALI AND RICHARD C. FOWLER
University of Florida, IFAS,
Central Florida Research and Education Center,
P. O. Box 909, Sanford, FL 32771
ABSTRACT
The population trends of chironomid larvae in Lake Monroe in central
Florida and the occurrence of adult midges around residences and businesses
along the southern shore of the lake in Seminole County were studied
from January 1979 to July 1984. Glyptotendipes paripes Edwards and
Chironomus crassicaudatus Malloch were the predominant species as larvae
and as adults. Larval densities (Ekman dredge samples) of G. paripes and
C. crassicaudatus fluctuated between <1 and >6000 and <1 and ca.
1800/m2, respectively. The density of total midge larvae was the highest (ca.
7000/m2) in August 1979 and the lowest (100/m2) in July 1982. There was a
decline of SO'., of total larvae in the lake in 1983 as compared to 1979. In
New Jersey light trap collections, G. paripes was the predominant species
(>70%) in 1980. It was outnumbered by C. crassicaudatus (60% of all
midges) in 1981 and 1982. In 1983, populations of G. paripes returned to
63% while C. crassicaudatus declined to 6% of the total adults. Peaks of
adult emergence usually occurred from May to November when in some
catches >500,000 adult midges were taken in a trap in 1 night. There was
a considerable reduction (up to 93%) of adult midges in the study area
from 1981 to 1984. This reduction was primarily due to the lower number
of G. paripes and C. crassicaudatus.
RESUME
De Enero 1979 a Julio 1984 se estudi6 la tendencia de poblaciones de las
larvas "chironomid" en el lago Monroe en el Condado de Seminole en el
centro de la Florida, y la ocurrencia de estas moscas enanas adults alrede-
dor de residencias y negocios a lo largo de la orilla sur del lago. Glyptoten-
dipes paripes Malloch, fueron las species predominantes como larvas y
adults. La densidad de las larvas (muestras de draga Ekmar) G. paripes y
C. crassiccaudatus fluctu6 entire <1 y >6000, y <1 y approx. 1800/m2 re-
spectivamente. La densidad total de larvas fue mas alta (approx. 7000/m2 en
Agosto de 1979 y mas baja (100/m2) en Julio de 1982. Hubo una reducci6n
de un 80% del total de larvas en el lago en 1983 cuando se compare con 1979.
G. paripes fue la especie predominante (>70%) colectada en trampas de luz
tipo New Jersey en 1980. Estos nimeros fueron excedidos por C. crassicauda-
tus (60% de todas las moscas enanas) en 1981. En 1983, poblaciones de G.
paripes volvio a 63% mientras que C. crassicaudatus baj6 un 6% del total
de los adults. La salida mas grande de los adults usualmente fue de Mayo
a Noviembre, cuando algunas captures fueron >500,000 adults en una
trampa en una noche. Hubo una reduction considerable (hasta un 93%) de
adults enanos en el afio estudiado de 1981 a 1984. Estas reducciones fueron
principalmente debidas al bajo numero de G. paripes y C. crasicaudatus.
June, 1985
304
Ali & Fowler: Decline of Chironomid Populations 305
Non-biting aquatic midges (Diptera :Chironomidae) frequently emerge in
phenomenal numbers from a variety of habitats. In many parts of the
world massive swarms of midges are a serious nuisance to man and live-
stock because they restrict outdoor activity and, in extreme cases, may cause
asphyxia (Cranston et al. 1983). Ali (1980) gave details of the nature of
nuisance and economic problems caused by adult midges. Apart from the
nuisance and economic problems, Cranston et al. (1981) reported the associ-
ation of seasonal midge emergence from the Nile in Sudan with human
allergic reactions, such as asthma and allergic rhinitis. It is now believed
that chironomids are more than a local Sudanese problem, and are po-
tentially a worldwide cause of allergy (Cranston et al. 1983).
In the last decade, the City of Sanford in central Florida frequently
experienced massive emergences of midges primarily from the adjacent Lake
Monroe. In 1977, a "blind mosquito" task force study undertaken by the
Greater Sanford Chamber of Commerce revealed that at least 10 counties
of Florida have midge problems and that Sanford alone suffers an annual
economic loss of 3-4 million dollars. This paper reports population trends of
chironomid larvae in Lake Monroe from January 1979 to July 1984, and
the occurrence of adult midges around Sanford waterfront businesses and
residences from January 1980 to July 1984.
MATERIALS AND METHODS
Lake Monroe is in Seminole and Volusia counties of central Florida. The
St. Johns River is the lake water source as well as discharge. The lake is ca.
8.5 km long and 6.0 km wide at its widest point. It has a surface area of ca.
4000 ha and a 20 km shoreline. Water in Lake Monroe remains turbid
throughout the year and ranges in depth from <1 m at the perimeter to
3.0 m in some central portions. Sediments in the lake are primarily mud,
sand, and fine silt. The City of Sanford borders the lake along the southern
5-6 km shoreline.
Twenty stations in the lake, established and marked for sampling midge
larvae, were reported in a previous study by Ali and Baggs (1982). The
larval samples were collected biweekly from January 1979 to March 1981,
monthly from April 1981 to April 1982, and bimonthly or quarterly from
May 1982 to July 1984. A minimum of 3 samples of benthic mud was taken
at each station by using a 15x15x30 cm Ekman dredge. Each sample was
washed and processed as described in Mulla et al. (1971). The processed
samples were examined in the laboratory by the method of Ali et al.
(1977), and midge larvae were identified and counted. At the time of
sampling, measurements of water temperature at surface and bottom of the
lake were taken at each station by using a YSI meter (Model 54-A, Yellow
Springs Instrument Co., OH). The daily air temperature data were obtained
from a nearby permanent recording station maintained at the Central
Florida Research and Education Center of the University of Florida.
Four New Jersey light traps were used to study the prevalence of adult
midges. Each trap was fitted with a 60-watt bulb and a photoelectric
switch. The traps were placed 1-2 km apart on premises of waterfront
businesses and residences in Sanford along the southern 5-6 km shore of
Lake Monroe. The traps were hung 2-3 m above ground level. Adult midges
Florida Entomologist 68(2)
were collected daily from each trap from January 1980 to July 1984, except
for the weekends when a 3 nights' catch was taken every Monday. Also, on
some holidays, the adults accumulated for 2-4 days. In the laboratory, adult
midges in each sample were segregated into species or genera and counted.
Samples containing large numbers (>50,000 adults/trap/night) were sub-
sampled by weight but at least 1/16th portion of the large samples was
completely counted and taxonomically determined.
RESULTS AND DISCUSSION
Species Composition. Among Chironomini, Glyptotendipes paripes Ed-
wards, Chironi, tus crassicaudatus Malloch, Chironomus decorus Johannsen,
Chironomus sp., Parachironomus sp., Goeldichironomus cars (Townes),
Goeldichironomus holoprasinus (Goeldi), Cryptochironomus fulvus Johann-
sen, and Polypedilum halterale (Coquillett) occurred in the larval and
adult collections. The Tanytarsini were represented by several species of
Tanytarsus and Rheotanytarsus. The Tanypodinae were comprised of Coelo-
tanypus concinnus (Coquillett), Coelotanypus scapularis (Loew), and Pro-
cladius sublettei Roback. The Orthocladiinae were represented by species
of Cricotopus. A few other chironomid species of minor quantitative im-
portance in the study area also occurred in the collections.
Larval Populations. Population trends of midge larvae, water tempera-
ture in Lake Monroe, and air temperature near the study area, covering
the period from January 1979 to July 1984 are shown in Fig. 1. Among all
midge species, G. paripes and C. crassicaudatus were quantitatively im-
portant. It was not possible to separate 1st and 2nd instars of ('l,,imrnori,;
spp. (particularly C. crassicaudatus and C. decorus) into species due to
taxonomic difficulties, therefore, all were included in C. crassicaudatus.
Glyptotendipes paripes and C. crassicaudatus formed 87% of the total
chironomid larvae in the lake in 1979. Their populations comprised 31-82%
of the total chironomids in the subsequent years. In 1983, the 2 species
totaled 31% of the total midge larvae. Each year, the larval populations
generally increased during the spring and summer seasons when the air
and water temperatures increased. The larval populations decreased during
the autumn and winter months with the decreasing air and water tempera-
tures (Fig. 1). The highest mean density of G. paripes (>6000 larvae/m2)
was recorded in August 1979. In subsequent years, G. paripes decreased con-
siderably and fluctuated from <1 to 80 larvae/m2 in the periodic collections.
From 1980 to 1983, the mean larval density of G. paripes did not exceed
80/m2 even during the summer months. In contrast to G. paripes, C. crassi-
caudatus gradually increased and predominated in the lake from 1980 to
1983. Chironomus crassicaudatus achieved the highest mean density (ca.
1800 larvae/m2) in June 1980. Larvae of Tanypodinae (mostly C. concinnus
and P. freeman) did not show pronounced seasonal trends. Tanypodinae
fluctuated from 20 to 500 larvae/m2 during the sampling period and formed
from 12% of the total chironomids in 1979 to 56% in 1983. The highest
density of total chironomid larvae in the lake existed in 1979 when ca. 7000
larvae/m2 were taken. In subsequent years, the total density fluctuated be-
tween 110 and 1700/m2. There was a decline of 80% of total midge larvae
in the lake in 1983 as compared to 1979 and this was mainly due to the
population reductions of G. paripes and to an extent, C. crassicaudatus.
The trend of the larval decline in the lake continued in 1984.
306
June, 1985
Ali & Fowler: Decline of Chironomid Populations 307
Air Temp. o Water Temp
S30- 30
lo-o m
JFMAMJJASONJFMAMJJASONDJFMAMJJASONbFMAMJJASONDJFMAMJJASONDJFMAMJJ
1979 1980 1981 1982 1983 1984
0 Total Chironomidae
TanyDodinae
10000 -a Other Chironomd ae -O O
SChiron mus crassicaudatus
G olyptotendip es p ipes
1000 1000 >
JFMAMJJASON JFMAMJJASON JFMAMJJASONJFMAMJJAS ON JFMAMJJASON JFMAMJJ
1979 1980 1981 1982 1983 1984
Fig. 1. Population trends of chironomid midge larvae in Lake Monroe,
Seminole and Volusia Counties, FL (January 1979-July 1984). The water
temperature represents the daytime mean of surface and bottom tempera-
tures taken periodically at 16-20 larval sampling stations in the lake. The
air temperature is the monthly average of the mean of daily maximum and
minimum temperatures recorded near the study area.
Adult Populations. Figure 2 shows the monthly population changes of
adult chironomids along lakefront Sanford from January 1980 to July 1984;
the seasonal trends are summarized in Table 1. Glyptotendipes paripes was
the predominant species (>70%) taken in the light traps in 1980. However,
in 1981, C. crassicaudatus outnumbered G. paripes (Table 1). In 1982, C.
crassicaudatus remained the most numerous (60%) of all midges while G.
paripes declined to levels of <1% of the total adults. In the following year,
populations of G. paripes returned to 63% of the total adults while those of
C. crassicaudatus decreased to 6% of the total adults. The annual mean per-
cent composition of Tanypodinae during the study period fluctuated between
5 and 15% of the total adults. Other Chironomidae (predominantly C. fulvus,
P. halterale, and Tanytarsus spp.) formed <1 to 21% of the total adults
taken annually from 1980 to 1983 but in the winter and spring of 1984, they
predominated in the collections. Each year, adult populations of all midge
species remained very low during the winter months, gradually increasing
in March-April and thereafter attaining several peaks from May to No-
vember when the air temperatures and the water temperatures in Lake
Monroe generally remained above 180C (Fig. 2). In the warmer periods,
the number of total adults taken daily in a trap varied considerably, rang-
ing from 0 to >500,000. A comparison of total adults taken each year shows
considerable reductions (up to 93%) of adult midges at lakefront Sanford
from 1981 to 1984. These reductions were primarily due to the lower
numbers of G. paripes and C. crassicaudatus.
308 Florida Entomologist 68 (2) June, 1985
SAir Temp. o Waer Temp.
020 Z 30
00 -25 m
20 20 Z'
15 15 "
o- -
< 100
Wi -5 5
0-
JFMAMJJASONDJMJJAJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJ
1980 1981 1982 1983 1984
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most obvious, affecting seasonal cycles and abundance of aquatic insects in-
cluding chironomids (Ali et al. 1977, Elliott 1967). Other factors, such as
z >
This long-term study clearly indicates that G. paripes and C. crassicanda-
responded with their prevailing high larval densities in the lake. Tany-
-o z
0- z
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< r
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-0 0
G. paripes, C. crassicaudatus, and C. decorous are less noticeable and may not
JFMAMJJASONDJFMMJSONJFAMJJAONJFMAMJJASONDJFMAMJJ
1980 1981 1982 1983 1984
Fig. 2. Monthly distribution of adult chironomid midges occurring in
New Jersey light traps located along lakefront, Lake Monroe, Sanford, FL
(January 1980-July 1984). Explanation for air and water temperatures are
the same as in Fig. 1.
The quantitative composition of populations of midge species may
change from year to year under the influence of a number of intrinsic and
extrinsic factors. Among these factors, temperature is regarded as the
most obvious, affecting seasonal cycles and abundance of aquatic insects in-
cluding chironomids (Ali et al. 1977, Elliott 1967). Other factors, such as
the availability of phytoplankton and zooplankton (midge food), the nature
and intensity of local oviposition, extent of natural enemies, competition
for food and space, and the prevailing chemical conditions may also sig-
nificantly influence the seasonal quantitative differences of midge species.
This long-term study clearly indicates that G. paripes and C. crassicauda-
tus, and to a lesser extent C. decorus are the primary pest species of midges
in the Sanford area and are permanent inhabitants of Lake Monroe. The
periodic abundance of adults of these species in Sanford generally cor-
responded with their prevailing high larval densities in the lake. Tany-
podinae and other Chironomidae, such as P. halterale, C. fulvus, and
Tanytarsus spp., at times, comprise significant numerical proportions of the
total adults. However, these midges due to their smaller adult size than
G. paripes, C. crassicaudatus, and C. decorus are less noticeable and may not
be considered as pestiferous at the levels of emergence recorded during the
5 years of this investigation.
Ali & Fowler: Decline of Chironomid Populations
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Ali & Fowler: Decline of Chironomid Populations 311
The quantitative threshold of tolerance level of adult midges by the
residents of Sanford area is not known. However, the reduced levels of
midge emergence and prevalence during 1982 to 1984 can be considered
tolerable because in this period no articles concerning the midge problem
appeared in the local newspapers and also no significant complaints (tele-
phone calls) from Sanford lakefront residents and business owners, usually
affected by midge swarms, were received by the University of Florida's
Central Florida Research and Education Center (CFREC) at Sanford. In
contrast, during the warmer months of 1979 and 1980, at least 2 articles
on the midge problem had appeared each year in the local newspapers and
at least 2-3 telephone calls from midge affected personnel were received
every week at the CFREC-Sanford during the 2 years.
ENDNOTE
Florida Agricultural Experiment Stations Journal Series No. 5810.
REFERENCES CITED
ALI, A. 1980. Nuisance chironomids and their control: a review. Bull.
Entomol. Soc. America 26: 3-16.
ALI, A., AND R. D. BAGGS. 1982. Seasonal changes of chironomid popula-
tions in a shallow natural lake and in a man-made water cooling
reservoir in central Florida. Mosquito News 42: 76-85.
ALI, A., M. S. MULLA, B. A. FEDERICI, AND F. W. PELSUE. 1977. Seasonal
changes in chironomid fauna and rainfall reducing chironomids in
urban flood control channels. Environ. Entomol. 6: 619-622.
CRANSTON, P. S., M. O. GAD EL RAB, AND A. B. KAY. 1981. Chironomid
midges as a cause of allergy in the Sudan. Trans. R. Soc. Trop. Med.
Hyg. 75: 1-4.
CRANSTON, P. S., R. D. TEE, P. F. CREDLAND, AND A. B. KAY. 1983. Chirono-
mid hemoglobins: their detection and role in allergy to midges in
the Sudan and elsewhere. Mem. American Ent. Soc. 34: 71-87.
ELLIOTT, J. M. 1967. The life histories and drifting of the Plecoptera and
Ephemeroptera in a Dartmoor stream. J. Anim. Ecol. 36: 343-61.
MULLA, M. S., R. L. NORLAND, D. M. FANARA, H. A. DARWAZEH, AND D. W.
MCKEAN. 1971. Control of chironomid midges in recreational lakes.
J. Econ. Entomol. 65: 300-307.
312 Florida Entomologist 68 (2) June, 1985
COMPARATIVE TOXICITIES OF SYNTHETIC
PYRETHROIDS TO THE FALL ARMYWORM,
SPODOPTERA FRUGIPERDA
GINGER L. GIST1 AND CHARLES D. LESS
Department of Entomology and Plant Pathology
University of Tennessee
Knoxville, TN 37996-4500 USA
ABSTRACT
Nine synthetic pyrethroids were tested in the laboratory for toxicity to
third and sixth instar fall armyworm (FAW), Spodoptera frugiperda (J. E.
Smith) (Lepidoptera: Noctuidae). LD,, values for 3rd instar FAW ranged
from 0.0041 pg/insect (permethrin [FMC]) to 0.1558 pg/insect (Ammo).
All pyrethroids were more toxic than diazinon. LD,, values for 6th instar
ranged from 0.213 pg/insect (permethrin [FMC]) to 5.841 /g/insect
(Ammo). Ammo was the only pyrethroid less toxic than diazinon to 6th
instar.
RESUME
Se evaluaron en el laboratorio nueve pyrethroids para toxicidad hacia el
tercer y sexto estadio del cogollero, Spodoptera frugiperda (J. E. Smith)
(Lepidoptera: Noctuidae). Valores de LD,, para el 3er. estadio del cogollero
vari6 de 0.0041 pg/insecto (permethrin (FMC)) a 0.1558 ag/insecto
(Ammo). Todos los pyrethroids fueron mis t6xicos que diazinon. Los
valores de LDso para el 6to. estadio vari6 de 0.213 pg/insecto (permethrin
[FMC], a 5.841 /g/insecto (Ammo). Ammo fue el finico pyrethroid menos
toxico que diazinon hacia el 6to. estadio.
The synthetic pyrethroids, first described in 1973, have been cited for
their potential as agricultural pest control agents (Breese 1977, Elliott et
al. 1978, Hall 1979, Harris and Svec 1976, Schmidt et al. 1976). The degree
of control of the fall armyworm (FAW), Spodoptera frugiperda (J. E.
Smith), one of the most important insect pests in the southeast United
States, (Fuxa 1982, Mitchell 1979), with the synthetic pyrethroids has
varied. Bass (1978) reported poor control in peanuts with Ambush@ and
Pydrin@ and unacceptable control on grain sorghum from Pounce@,
Pydrin, and FMC 45498. However, Wood et al. (1981) found permethrin
to be more toxic than methyl parathion, trichlorfon, or carbaryl to FAW
larvae reared on various diets.
The purpose of this study was to evaluate contact toxicities of 9 syn-
thetic pyrethroids to a laboratory strain of FAW.
MATERIALS AND METHODS
Larvae used in contact toxicity tests were from a laboratory reared
'Current Address: Department of Environmental Health, Box 22960 A, East Tennessee
State University, Johnson City, TN 37614-0002.
I ___I
Gist & Pless: Toxicities of Pyrethroids
colony established in February 1982 with pupae obtained from the Southern
Grain Insects Research Laboratory in Tifton, Georgia. The insects were
reared on artificial diet (Bio-Serv Corn Earworm Rearing Media, Bio-Mix
#9394) according to a procedure modified from Perkins (1979).
One liter of insecticide-acetone (wt/vol) solution was applied to the
dorsal thoracic region of 3rd or 6th instars with a syringe microburet.
Larvae were placed into individual 5 cm diam petri dishes and allowed to
feed on artificial diet. Larvae were maintained in environmental chambers
at 270 20C, 14:10 L:D, and 60-70% RH. Mortality, determined by failure
to respond to probing, was recorded at 24 h.
Preliminary dosages of insecticides were used to establish mortality
ranges. Dosages-mortality regression lines, obtained by probit analysis
(Finney 1964), provided LDo5 values, confidence intervals, LDo9 values, and
slopes for each insecticide for 5-10 dose levels using a minimum of 30
larvae/dose. A toxicity index (Sun 1950) was used to compare the toxicity
of each synthetic pyrethroid with that of diazinon, an organophosphate used
as a standard.
The synthetic pyrethroids were technical formulations of permethrin
and cypermethrin (ICI Americas, Inc.); permethrin, cypermethrin, Pounce,
and Ammo@ (FMC Agricultural Chemical Group); Pydrin (Shell De-
velopment Co.); Mavrik (Zoecon Corp.); and Pay-Off@ (American Cyana-
mid Co.).
RESULTS AND DISCUSSION
The pyrethroids were 3 to 120 times more toxic than diazinon to 3rd
instar (Table 1). LD5o values ranged from 0.1558 pg/insect (Ammo) to
0.0041 pg/insect (permethrin [FMC]), representing a 38-fold decrease in
concentration. Relatively flat regression lines for Pydrin, cypermethrin
(ICI), and Ammo suggest heterogenous responses (Hoskins and Gordan
1956), indicating a possible tolerance to those insecticides by portions of
the population.
The synthetic pyrethroids, with the exception of Ammo, were also
effective contact insecticides to 6th instar FAW (Table 2). LDo5 values
ranged from 5.841 pg/insect (Ammo) to 0.213 pg/insect (permethrin
TABLE 1. COMPARATIVE TOXICITIES OF NINE SYNTHETIC PYRETHROIDS TO
LABORATORY-REARED 3RD INSTAR FALL ARMYWORM.
LD,, LDo0 Toxicity
Compound Ag/insect C.L. pg/insect slope index
permethrin (FMC) 0.0041 0.0036-0.0045 0.0102 3.82 11,968
permethrin (ICI) 0.0067 0.0062-0.0071 0.0110 5.67 7,324
Pounce@ 0.0271 0.0178-0.0354 0.0590 3.10 1,811
cypermethrin (FMC) 0.0307 0.0104-0.0407 0.1053 2.73 1,598
Pay-Off@ 0.0407 0.0275-0.0696 0.1215 2.70 1,207
Mavrik@ 0.0487 0.0309-0.0507 0.0776 4.74 1,008
Pydrin 0.1277 0.0712-0.1701 0.5808 1.95 384
cypermethrin (ICI) 0.1327 0.1301-0.2104 0.9445 1.69 370
Ammo@ 0.1558 0.1390-0.2291 0.9339 1.71 315
diazinon 0.4907 0.4883-0.5158 1.0321 2.87 100
313
Florida Entomologist 68 (2)
June, 1985
TABLE 2. COMPARATIVE TOXICITIES OF NINE SYNTHETIC PYRETHROIDS TO
LABORATORY REARED 6TH INSTAR FALL ARMYWORM.
LDo5 LDo Toxicity
Compound pg/insect C.L. pg/insect slope index
permethrin (FMC) 0.213 0.200-0.372 0.561 2.49 1,820
cypermethrin (FMC) 0.250 0.187-0.687 0.788 2.87 1,550
Pay-Off@ 0.306 0.190-0.385 0.978 2.78 1,267
permethrin (ICI) 0.662 0.649-0.706 1.122 5.23 585
cypermethrin (ICI) 0.684 0.501-0.882 1.289 5.50 567
Pydrin 0.813 0.524-1.214 1.574 5.26 477
Mavrik@ 1.456 0.340-1.657 7.435 2.83 266
Pounce@ 3.471 2.044-4.202 7.100 4.20 112
Ammo@ 5.841 5.204-6.582 11.847 3.91 66
diazinon 3.876 3.477-4.000 10.980 4.63 100
[FMC]), a 27-fold decrease in concentration. The pyrethroids, except
Pounce@ and Ammo were from 2.5 to 18 times more toxic than diazinon to
6th instar. Pounce@ had approximately the same toxicity as diazinon, and
Ammo@ was approximately 0.67 as toxic as diazinon. All pyrethroids had
relatively steep regression lines indicating a homogenous response. This is
a characteristic for insect populations that have not been exposed to any
significant chemical selection pressure which allows a buildup of tolerance
to the toxicant (Hoskins 1960).
Third instar larvae were more susceptible to the pyrethroids than were 6th
instar. Differences in susceptibility ranged from 5X (cypermethrin [ICI])
to 128X (Pounce@). Diazinon was ca. 8X more toxic to 3rd instar than to
6th instar.
Within 10 min after treatment with pyrethroids at any concentration
larvae displayed symptoms of pyrethroid poisoning (Ford et al. 1977),
including initial hyperactivity, fluid loss due to regurgitation and version
of the rectum, loss of coordination, knockdown leading to paralysis, and
death. These reactions to poisoning may provide additional protection to
plants by dislodging surviving insects and/or exposing them to increased
predation. Water loss may also contribute to mortality, especially in hot
summer weather.
McDonald (1979) found pyrethroids in general to be more toxic than
organophosphates to the army cutworm. In this study, the pyrethroids were
found to be more toxic than diazinon to FAW larvae even though the modes
of action of the two insecticide classes are thought to be similar. Synthetic
pyrethroids are better contact poisons than oral poisons (McDonald 1976),
possibly because of their feeding deterrent properties (Gist and Pless
1985) which cause the insect to avoid ingesting the toxin.
The difference in toxicities of the pyrethroids in the laboratory vs the
field can be partially explained by the absence of selective pressure in the
laboratory population, demonstrated by the relatively steep dosage-mor-
tality lines. Variation in toxicities to FAW has been explained on the
basis of insect resistance (Farnham and Sawicki 1976), tolerance, cross
resistance (Crowder et al. 1979, Twine and Reynolds 1980), and differences
in the host crop (Wood et al. 1981). Because susceptibility of FAW to in-
314
Gist & Pless: Toxicities of Pyrethroids
315
secticides varies with the crop upon which they are feeding (Wood
et al. 1981), additional field evaluations are needed to correlate efficacy in
the field with that in the laboratory.
REFERENCES CITED
BASS, M. H. 1978. Fall armyworm: Evaluation of insecticides for control.
Agric. Exp. Stn. Auburn Univ. Leaflet 93: 7.
BREESE, M. H. 1977. The potential for pyrethroids as agricultural, veterinary,
and industrial insecticides. Pestic. Sci. 8: 264-269.
CROWDER, L. A., M. S. TOLEFSON, AND T. F. WATSON. 1979. Dosage-mortality
studies of synthetic pyrethroids and methyl parathion on the tobacco
budworm in Central Arizona. J. Econ. Entomol. 72: 1-3.
ELLIOT, M., N. F. JANES, AND C. POTTER. 1978. The future of pyrethroids in
insect control. Annu. Rev. Entomol. 23: 443-469.
FARNHAM, A. W., AND R. W. SAWICKI. 1976. Development of resistance to
pyrethroids in insects resistant to other insecticides. Pestic. Sci. 7:
278-282.
FINNEY, D. J. 1964. Probit analysis. Cambridge Univ. Press. P. 318.
FORD, M. G., R. C. REAY, D. PERT, P. E. ELLIS, AND L. J. MCVEIGH. 1977.
Toxicity of pyrethroids to larvae of the Egyptian cotton leafworm,
Spodoptera littoralis (Boisd.). I. Relative toxicities and knockdown
activities of benzyl, and 5-benxyl-3-furylmethyl, cyclopropanecarboxy-
lates. Pestic. Sci. 8: 203-210.
GIST, G. L. AND C. D. PLESS. 1985. Feeding deterrent effects of synthetic
pyrethroids on the fall armyworm, Spodoptera frugiperda. Florida
Entomol. (In press).
HALL, F. R. 1979. Effects of synthetic pyrethroids on major insect and
mite pests of apple. J. Econ. Entomol. 72: 441-446.
HARRIS, C. R. AND H. J. SVEC. 1976. Susceptibility of the Colorado potato
beetle in Ontario to insecticides. Ibid. 69: 625-629.
HOSKINS, W. M. 1960. Use of the dosage-mortality curve in quantitative
estimation of insecticide resistance. Misc. Publ. Entomol. Soc. Am.
2: 85-91.
MCDONALD, S. 1976. Evaluation of several new insecticides for the control
of the Colorado potato beetle and the status of DDT resistance in
southern Alberta. J. Econ. Entomol. 69: 659-664.
MITCHELL, E. R. 1979. Preface to fall armyworm symposium. Florida
Entomol. 62: 81.
PERKINS, W. D. 1979. Laboratory rearing of the fall armyworm. Ibid. 62:
87-91.
SCHMIDT, C. D., J. J. MATTER, J. H. MEUER, R. E. REEVES, AND B. K. SHELLEY.
1976. Evaluation of a synthetic pyrethroid for control of stable flies
and barn flies on cattle. J. Econ. Entomol. 69: 484-486.
SUN, Y. P. 1950. Toxicity index-an improved method of comparing the
relativity toxicity of insecticides. Ibid. 43: 45-53.
TWINE, P. H. AND T. H. REYNOLDS. 1980. Relative susceptibility and re-
sistance of the tobacco budworm to methyl parathion and synthetic
pyrethroids in Southern California. Ibid. 72: 239-242.
WOOD, K. A., B. H. WILSON, AND J. B. GRAVES. 1981. Influence of host plant
on the susceptibility of the fall armyworm to insecticides. Ibid. 74:
96-98.
316 Florida Entomologist 68 (2) June, 1985
SYNERGISTIC ACTIVITY OF PIPERONYL BUTOXIDE
WITH NINE SYNTHETIC PYRETHROIDS AGAINST
THE FALL ARMYWORM, SPODOPTERA FRUGIPERDA
GINGER L. GIST1 AND CHARLES D. PLESS
Department of Entomology and Plant Pathology
University of Tennessee
Knoxville, TN 37901-1071 USA
ABSTRACT
Nine synthetic pyrethroids were evaluated in the laboratory for synergis-
tic activity with piperonly butoxide (1:8) when used on fall armyworm,
Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). The
cypermethrins (FMC Agricultural Chemical Group and ICI Americas, Inc.)
were the only pyrethroids to have significant (Synergistic Ratio = 3.531 and
6.328 respectively) synergistic activity to eggs. Cypermethrin (FMC) (SR =
3.0700) and Ammo@ (SR = 9.1111) were significantly synergized for 3rd
instar. Ammo (SR = 8.641) was significantly synergized for 6th instar.
RESUME
Se evaluaron en el laboratorio nueve pyrethroids sint6ticos para activi-
dades sinergeticas con piperonyl butoxide (1:8) cuando se usaron contra el
cogollero, Sodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae).
Los cypermethrins (FMC Agricultural Chemical Group and ICI Americas,
Inc.) eran los finicos pyrethroids que tuvieron una significant actividad
sinerg6tica hacia los huevos (una proporci6n sinerg6tica = 3.531 y 6.328 re-
spectivamente). Cypermethrin (FMC) (Reacci6n Sinerg6tica = 3.0700) y
Ammo (Reacci6n Sinerg6tica = 9.1111) fue significantemente siner-
g6tico hacia el 3er. estadio. Ammo@ (Reacci6n Sinergetica = 8.641) fue
significantemente sinerg6tico hacia el 6to. estadio.
Insecticidal synergism can be defined as increased activity (of an in-
secticide) resulting from the effect of one chemical on another. The first
commercial synergist was introduced in 1940 to increase the effectiveness
of the botanical insecticide, pyrethrum. Since that time it has been well
established that synergists increase the effectiveness of pyrethroids by re-
ducing their rate of metabolism in insects (Casida 1970, Jao and Casida
1974a,b, Yamamoto 1973).
The optimal synergist varies with the insect species and pyrethroid
(Jao and Casida 1974a) as well as the stage of the insect's development. Yu
(1983) pointed out that activities of various detoxifying enzymes fluctuate
during the life stages of insects, thus low activity of these enzymes would
indicate a susceptible period and vice versa. Piperonyl butoxide (PB), an
oxidase inhibitor is the most commonly used synergist, although reports of
'Current Address: Department of Environmental Health. Box 22960 A, East Tennessee
State University, Johnson City, TN 37614-0002.
Gist & Pless: Synergism of Pyrethroids 317
activity have varied (Casida 1970, Chang and Jordan 1982, 1983, Jao and
Casida 1974a, Lloyd and Ruczkowski 1980).
The purpose of this study was to evaluate the synergistic activity of
piperonyl butoxide with 9 synthetic pyrethroids to a laboratory strain of fall
armyworm (FAW), Spodoptera frugiperda (J. E. Smith).
MATERIALS AND METHODS
Procedures for ovicidal tests have been previously reported (Gist and
Pless 1985b). Briefly, egg masses were treated by dipping them into ace-
tone solutions of insecticide: PB. Each treatment was applied to 75-100
eggs and replicated 3 times. Eggs which hatched were counted daily for
7 days.
Larvae were reared and treated according to procedures detailed pre-
viously (Gist and Pless 1985a). Third and 6th instars were treated with
1 pl applications of insecticide: PB. Each treatment was applied to 3 repli-
cates of 10 larvae/instar. Mortality was determined after 24h.
Insecticide-acetone (wt/vol) :synergist-acetone (wt/vol) (1:8) solutions
were tested. Preliminary dosages of insecticide :synergist solutions were used
to establish mortality ranges. Dosage-mortality regression lines, obtained
by probit analysis (Finney 1964) provided LC50 or LD50 values for each
insecticide:synergist solution for 5-10 dose levels. Synergistic ratios (LCso
or LDso of pyrethroid alone/LCo0 or LD5s of pyrethroid + synergist) were
established with LCo, or LDo0 values from Gist and Pless (1985a,b). The
Mann-Whitney U Test was used to determine significance of synergised vs.
nonsynergised comparisons.
Synthetic pyrethroids used in this study were technical formulations of
permethrin and cypermehtrin (ICI Americas, Inc.); permethrin, cyper-
methrin, Pounce@, and Ammo@ (FMC Agricultural Chemical Group);
Pydrin (Shell Development Co.); Mavrik@ (Zoecon Corp.); and Pay-
Off@ (American Cyanamide Co.). The synergist 11sed was Prentox PBO
8@ (91.3% technical piperonyl butoxide) (Prentiss Drug and Chemical Co.,
Inc.).
RESULTS AND DISCUSSION
The pyrethroids were not readily synergised by PB when applied to
FAW (Table 1). The only pyrethroids to have synergistic activity on eggs
were cypermethrin (FMC) (SR __ 3.5) and cypermethrin (ICI) (SR 6.3).
Cypermethrin (FMC) (SR ~ 3.1) and Ammo@ (SR 9.1) had synergistic
activity on 3rd instar. Ammo@ (SR ~ 8.6) was the only pyrethroid to have
synergistic activity on 6th instar. All of the above synergistic ratios are in
the low to slightly moderate range of synergism.
For metabolic research, synergism is usually investigated by applying
a synergist followed by an application of the active insecticide (Elliot and
Janes 1978). This method would not be practical in field situations; there-
fore, it was not used in this study.
The cypermethrins (ICI, FMC, and Ammo) were the only pyrethroids
to show synergistic activity on FAW. In each case, synergism decreased with
increased age of the insects. Chang and Jordan (1982) showed that per-
methrin penetrated into Wiseana cervinata larvae faster than cypermethrin.
Casida (1970) pointed out that most well-known synergists, including PB,
318 Florida Entomologist 68 (2) June, 1985
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Gist & Pless: Synergism of Pyrethroids
319
are fat-soluble and therefore favor penetration through the insect cuticle.
Pepper and Hastings (1943) and Gast (1961) found that, during larval de-
velopment, the insect cuticle varied in its composition. For example, lipid
content causes changes in insecticide susceptibility. Thus, it is possible that
the small residual factor of synergism shown by cypermethrin may be
explained by physical effects of the large dose of lipophilic synergist on pene-
tration as well as the increased penetration of the pyrethroid itself. The
decrease in insecticide susceptibility with increased larval age of FAW
could also be due to an increase in insecticide metabolizing enzymes in
older larvae (Yu 1983).
Yu (1982) indicated that an increase in detoxifying enzymes due to host
plant induction results in a protective effect against various insecticides,
including pyrethroids, in FAW. This is supported by Wood et al. (1981) who
showed that FAW susceptibility to insecticides, including permethrin,
varied with the host plant. In view of this, addition of a synergist to pyre-
throids to increase their insecticidal potency and cost efficiency is tempting;
however, concomitant alterations in mammalian toxicity may shift com-
pounds otherwise considered safe into a hazardous category (Casida and
Ruzo 1980).
REFERENCES
CASIDA, J. E. 1970. Mixed function oxidase involvement in the biochemistry
of insecticide synergists. J. Agric. Food. Chem. 18: 753-72.
AND L. O. Ruzo. 1980. Metabolic chemistry of pyrethroid insecticides.
Pestic. Sci. 11: 257-69.
CHANG, C. K. AND T. W. JORDAN. 1982. Penetration and metabolism of
topically applied permethrin and cypermethrin in pyrethroid-tolerant
Wiseana cervinata larvae. Pestic. Biochem. Physiol. 17: 196-204.
AND 1983. Inhibition of permethrin hydrolyzing esterases
from Wiseana cervinata larvae. Ibid. 19: 190-195.
ELLIOTT, M. AND N. F. JANES. 1978. Synthetic pyrethroids-A new class of
insecticide. Chem. Soc. Rev. 7: 473-505.
FINNEY, D. J. 1964. Probit analysis. Cambridge University Press. 318 p.
GAST, R. R. 1961. Factors involved in differential susceptibility of corn ear-
worm larvae to DDT. J. Econ. Entomol. 54: 1203-1206.
GIST, G. L. AND C. D. PLESS. 1985a. Comparative toxicities of synthetic pyre-
throids to the fall armyworm, Spodoptera frugiperda. Florida
Entomol. 68: 312-315.
AND 1985b. Ovicidal activity and ovipositional deterrent
properties of synthetic pyrethroids on the fall armyworm, Spodop-
tera frugiperda. Ibid. (In press).
JAO, L. T. AND J. E. CASIDA. 1974a. Esterase inhibitors as synergists for
(+)-trans-chrysanthemate insecticide chemicals. Pestic. Biochem.
Physiol. 4: 456-464.
LLOYD, C. J. AND G. E. RUCZKOWSKI. 1980. The cross-resistance to pyrethrins
and eight synthetic pyrethroids, of pn organo-phosphorous-resistant
strain of the rust-red flour beetle, Tritolium castaneum (Herbst).
Pestic. Sci. 11: 331-340.
PEPPER, J. H. AND E. HASTINGS. 1943. Age variations in exoskeletal com-
position of the sugar beet webworm and their possible effect on
membrane permeability. Ibid. 36: 633-634.
WOOD, K. A., B. H. WILSON, AND J. B. GRAVES. 1981. Influence of host plant
on the susceptibility of the fall armyworm to insecticides. J. Econ.
Entomol. 74: 96-98.
320 Florida Entomologist 68 (2) June, 1985
YAMAMOTO, I. 1973. Mode of action of synergists in enhancing the insecti-
cidal activity of pyrethrum and pyrethroids. In Pyrethrum-The
natural insecticide. J. E. Casida (ed.). Pp. 195-210. Academic Press,
New York.
Yu, S. J. 1982. Induction of microsomal oxidases by host plants in the fall
armyworm, Spodoptera frugiperda (J. E. Smith). Pestic. Biochem.
Physiol. 17: 59-67.
---, 1983. Age variation in insecticide susceptibility and detoxification
capacity of the fall armyworm (Lepidoptera: Noctuidae) larvae. J.
Econ. Entomol. 76: 219-222.
CAULOTOPS DISTANT (MIRIDAE: HETEROPTERA),
A POTENTIAL YUCCA PEST NEWLY DISCOVERED
IN THE UNITED STATES
THOMAS J. HENRY
Systematic Entomology Laboratory, IIBIII
Agricultural Research Service, USDA
c/o U.S. National Museum, NHB 168
Washington, D.C. 20560
ABSTRACT
The plant bug Caulotops distant (Reuter) is reported for the first time
in the United States based on specimens collected in two Florida nurseries
damaging potted cuttings of Yucca elephantipes Regel (Agavaceae). Be-
cause come of the potted plant material infested with C. distant has been
sold, this potential Yucca pest is considered at least temporarily established
in the United States. Caulotops distant was imported from Costa Rica,
probably as eggs inserted in the stems of its host. A diagnosis and
key are provided to help separate C. distant from other U. S. species of
Caulotops and the morphologically similar Halticotoma valida Townsend.
RESUME
Se report por primera vez en los Estado Unidos a Caulopos distant
(Reuter), basado en muestras colectadas en dos viveros, dafiando plants de
Yucca elephantipes Regel (Agavaceae) sembradas en jarrones. Puesto que
algunas de estas plants infestadas con C. distant han sido vendidas, esta
possible plaga de Yucca es por lo menos temporalmente considerada estable-
cida en los Estados Unidos. Caulotopos distant fue importada de Costa Rica,
posiblemente como huevos insertados en los tallos del hospedero. Se provee
un diagn6stico y una clava para ayudar a separar a C. distant de otras
species de Caulotops de los Estados Unidos y del morfologicamente similar
Halticotoma valida Townsend.
The plant bug Caulotops distant (Reuter) is here reported for the first
time in the United States based on specimens submitted to the Systematic
Entomology Laboratory, IIBIII, Agricultural Research Service, USDA,
Washington, D.C. In this paper I outline the steps leading to the discovery
of this mirid, present comments on its economic potential, and provide a
diagnosis and key to the U. S. species of Caulotops.
Henry: New Yucca Pest In U.S. 321
Recently, I received 5 females of an undetermined Caulotops (submitted
by F. W. Mead, Fla. St. Colln. Arthropods, Gainesville) collected by Paul
Gibson in a nursery at Apopka, Orange Co., Florida, 6-VII-1984, on Yucca
elephantipes Regel (Agavaceae). A later collection (9-VIII-1984) by Mr.
Gibson (Fla. Dept. Agric.) of 33 specimens containing males taken in the
same nursery on potted Yucca elephantipes allowed me tentatively to identify
the species as Caulotops distant (Reuter). By comparing external morph-
ology and male genitalia to paratypes of Carvalho's C. rufoscutellatus (a
junior synonym of C. distant) series, I have been able to confirm my earlier
identification. Further, study of paratypes of the subspecies C. distant
major Carvalho, 1948, suggests that this Mexican form is only a color
variant of the nominate subspecies C. distant distant (Reuter) and is here
considered a synonym.
The original of the C. distant population has been traced to at least two
nurseries located in north central Florida. The plant material was imported
from Costa Rica as unrooted tips planted three per pot. At the time of im-
portation, the cuttings were inspected and considered pest free, indicating
that the population of C. distant probably arrived as eggs inserted in the
stems of the Y. elephantipes. Of the 375 original pots, 250 were sold and
distributed to buyers in Louisiana, Maryland, Massachusetts, Michigan,
Missouri, North Carolina, Ohio, Quebec, and Virginia. The remaining 125
pots were rendered unsalable in 6 months by the C. distant population and
have been destroyed.
Because the feeding habits and damage inflicted are similar to that of
Halticotoma valida Townsend (Wheeler, 1976), it is likely that yucca
plantings supporting populations of C. distant can be killed if this pest is
not controlled. It is doubtful that C. distant can survive in climates as far
north as Maryland or Virginia (or the northern range of H. valida), but
yucca plantings in the more southern states could be considered susceptible.
Because of the damage produced on the nursery stock in Florida, this species
should be considered a pest of ornamental Yucca elephantipes, and possibly
other native and ornamental Yucca spp.
Taxonomic history.-Caulotops distant was described in the genus
Euryciptia from Venezuela (Reuter, 1905) and later transferred to Ber-
groth's genus Caulotops (Reuter, 1908). Carvalho (1948) described the
species Caulotops rufoscutellatus, also from venezuela, and the subspecies
Caulotops rufoscutellatus major from Yucatan, Mexico (the latter here
considered only a color form of C. distanti. After studying type material,
Carvalho (1954) synonymized his species C. rufoscutellatus with C. distant.
The adult male and male genitalia [as C. rufoscutellatus] have been illustrat-
ed (Carvalho, 1948).
Distribution.-In addition to the Venezuelan [type-locality of C. rufo-
scutellatus], Mexican [type-locality of C. rufoscutellatus major], and Florida
specimens, I have examined a series of 17 adults and 7 nymphs in the
USNM collection that were taken on Yucca sp. at Brownsville, Texas, 19
Oct. 1944, apparently intercepted on plants originating from the Neotropics.
With these records, C. distant is now known to occur in Costa Rica, Mexico,
and Venezuela. Its establishment in the United States (possibly Florida,
Louisiana, North Carolina, Virginia, and Texas) needs further confirma-
tion.
Diagnosis of C. distanti.-Male: Length 3.40-3.62 mm, width 1.50-1.56 mm.
322 Florida Entomologist 68 (2) June, 1985
Head: Width 0.96-1.00 mm, width of vertex 0.62 mm. Rostrum: Length 1.26-
1.30 mm, extending slightly beyond bases of metacoxae. Antenna: Segment I,
length 0.44-0.46 mm; II, 0.60-066 mm; III, 0.56-0.62 mm; IV, 0.54-0.60 mm.
Pronotum: Length 0.64-0.70 mm, basal width 1.22-1.26 mm.
Female: Length 3.67-4.08 mm, width 1.67 mm. Head: Width 1.04-
1.06 mm, width of vertex 0.64-0.66 mm. Rostrum: 1.34-1.36 mm. Antenna: I,
0.46-0.48 mm; II, 0.62-0.68 mm; III, 0.64-0.66 mm; IV, 0.64-0.68 mm. Prono-
tum: Length 0.68-0.72 mm, basal width 1.32-1.38 mm.
General coloration of head, pronotum, scutellum, venter, and legs pale
yellowish brown to orange; hemelytra fuscous to bluish black. Head: Color
as above with epicranial suture stippled with red, frons with 7-8 transverse
brownish marks on each side of meson, these more distinct on pale, yellowish-
brown individuals, apex of tylus fuscous. Pronotum: Color as above with
calli infuscated on pale individuals; scutellum uniformly yellow to orange.
Hemelytra colored as above, usually with a pale yellow to orange wedge-
shaped streak beginning narrowly at base or middle of corium and broadly
expanding at cuneal fracture; membrane and veins fumate. Venter uni-
formly yellow to orange, abdomen sometimes slightly infuscated. Antenna:
Segment I pale yellowish brown, apex and narrow sub-basal ring fuscous;
segments II-IV fuscous. Legs: Yellowish to orange; bases of femora and
apices of coxae paler on orange individuals.
Remarks.-The genus Caulotops, previously represented in the United
States by C. agavis Reuter and C. barberi Knight (both known only from
Arizona), is most similar to the genus Halticotoma. Knight (1968) provided
a key to separate the two genera, using the form of the calli as the dis-
tinguishing character. As currently defined, species of Halticotoma have the
calli relatively smooth and undifferentiated, the body broadly rounded, and
the hosts are primarily species of Yucca (Agavaceae). Species of Caulotops
have distinctly raised calli with a depression between them, the body is more
slender and elongate, and the hosts generally are species of Agave (Agava-
ceae). Unfortunately, these morphological characters and host preferences
intergrade when all species in both genera are compared. A thorough analysis
of the two genera, with a comparison of genitalia, is needed to clarify their
relationships. The following key will separate the U.S. species of Caulotops.
Key to the U. S. species of Caulotops
1. Body length 4.1 mm or less; first antennal segment pale with apex and
sub-basal ring fuscous; central area of corium usually with yellow or
orange wedge-shaped streak ........-----................ distant (Reuter)
Body length 4.6 mm or greater; first antennal segment uniformly black;
hemelytron uniformly bluish black ---------..-------- ------. ----....... 2
2. Antennal segment II longer than width of vertex and single eye com-
bined; tubercle on left side of male genital segment thick and bluntly
rounded apically -----.----------------.----. ........... ...... agave Reuter
Antennal segment II shorter than width of vertex and single eye com-
bined; tubercle on left side of male genital segment slender and acute
apically ---.................-- .......---------------..-- --- barber Knight
In the eastern United States, C. distant keys to Halticotoma valida in
Blatchley (1926). C. distant is easily separated from H. valida by the
current generic definition of characters in having the body more slender
and the calli raised and separated by a distinct mesal groove. C. distant is
Henry: New Yucca Pest In U.S.
further separated from H. valida by the pale first antennal segment that
has the apex and a sub-basal ring fuscous (first segment uniformly black
on valida), the uniformly yellow or orange scutellum (scutellum mostly
fuscous on valida), and the larger size (valida ranges from 2.8-3.5 mm, but
most individuals are 3.0-3.3 mm).
ACKNOWLEDGMENTS
I thank F. W. Mead and P. Gibson for providing biological and regula-
tory information on this species.
REFERENCES CITED
BLATCHLEY, W. S. 1926. Heteroptera or true bugs of Eastern North America.
Nature Publ. Co., Indianapolis. 1116 pp.
CARVALHO, J. C. M. 1948. Mirideos neotropicais, XXXV: Generos "Corcovado-
cola" n. g., "Guanabarea" n. g. e "Caulotops" Bergroth (Hemiptera).
Rev. Brasil. Biol. 8: 525-533.
CARVALHO, J. C. M. 1954. Neotropical Miridae, LXXVII: Miscellaneous
observations in some European museums (Hemiptera). An. Acad.
Brasil. Ci. 26: 423-427.
KNIGHT, H. H. 1968. Taxonomic review: Miridae of the Nevada Test Site and
the Western United States. Brigham Young Univ. Sci. Bull. 9(3):
1-282.
REUTER, O. M. 1905. Capsidae in Venezuela a D:o D:re Fr. Meinert collectae
enumeratae novaeque species descriptae. 6fv. F. Vet.-Soc. Forh.,
Stockholm 47: 1-39.
REUTER, O. M. 1908. Capsidae Mexicanae a D:o Bilimek collectae in Museo
i.r. Vindobonensi asservatae enumeratae. Ann. Nat. Hofmus Wien
22: 150-179.
WHEELER, A. G., JR. 1976. Yucca plant bug, Halticotoma valida: Authorship,
distribution, host plants, and notes on biology. Fla. Ent. 59: 71-79.
NOTES ON THE GENUS EUPHYES, WITH
DESCRIPTION OF A NEW SUBSPECIES
(LEPIDOPTERA: HESPERIIDAE)
LEE D. MILLER
Allyn Museum of Entomology, Florida State Museum
3701 Bay Shore Road, Sarasota, Florida 33580
DONALD J. HARVEY
Department of Zoology, University of Texas, Austin, Texas 78712
AND
JACQUELINE Y. MILLER
Allyn Museum of Entomology, Florida State Museum
ABSTRACT
A new subspecies of Euphyes pilatka (W. H. Edwards) is described
from the Florida Keys and compared with the nominate subspecies. The
323
Florida Entomologist 68 (2)
June, 1985
subspecies of Euphyes conspicua (W. H. Edwards) are discussed, and the
name orono (Scudder) is resurrected for the east coast subspecies.
RESUME
Una subespecies nueva de Euphyes pilatka (W. H. Edwards) es de-
scrita de los Cayos de la Florida y comparada con la subespecies typical. Las
subespecies de Euphyes conspicua (W. H. Edwards) son discutidas, y el
nombre orono (Scudder) es restablecido para la subespecies de la costa este.
The genus Euphyes contains ten Nearctic species (L. Miller and F. M.
Brown 1981: 45-46), most of which are restricted to moist to swampy en-
vironments. Because of this ecological restriction, a number of taxa are
found only in small demes that are isolated from other such populations by
more or less uncrossable barriers. Most of the species have been considered
to be monomorphic throughout their ranges, but examination of long series
of these butterflies from several localities suggests that this situation is by
no means as simple as it seems. During the past 60 years a number of new
Euphyes, both species and subspecies, have been described (Lindsey 1923,
Bell 1941, Ehrlich and Gillham 1951, Freeman 1975, J. Brown and McGuire
1983). Thus, the recognition of other taxa should surprise no one.
The two species dealt with in this paper are both fairly common
throughout their ranges, but seldom is material from disparate localities
compared, most examinations being restricted to specimens from one or
two populations; the differences between demes cannot be detected unless
species are sampled from throughout their ranges.
Euphyes pilatka (W. H. Edwards), 1867
This name, originally spelled as above, was emended to "palatka" by
Scudder (1872: 80), based on the change of spelling of the Florida town
name from "Pilatka" to "Palatka". The emendation of the town's name was
promulgated by the U. S. Post Office, because it was felt that the original
spelling would cause confusion with the nearby town of Picolata (Morris
1974). The history of Scudder's unjustified emendation is further sum-
marized in F. M. Brown and L. Miller (1980: 83, 86).
This species is not uncommon in Florida and extends northward and
westward on the Coastal Plain to Virginia and Mississippi (MacNeill 1975:
448) wherever sawgrass, Mariscus jamaicensis Crantz (CYPERACEAE)
is prevalent in swampy habitats. Individual demes vary, but in many only
a few adults are present at any one time (populations on at least the south-
ern periphery of the range may have fewer than a dozen specimens flying,
though many additional members of the deme may be present as eggs,
larvae or pupae).
Almost all of the definitive records are from the mainland U. S., with
the exception of a single female recorded by Kimball (1965: 55-56) from
Sugarloaf Key, Monroe Co., Florida, which Klots reportedly suspected of
being representative of a new subspecies. Kimball, however, states that,
"Symmes has a series from Big Pine Key which are all definitely typical. .."
Nevertheless, we decided to investigate the Lower Keys population and
over a period of years have accumulated a significant number of specimens.
324
Miller et al.: New subspecies of Euphyes 325
None of the Big Pine Key, Sugarloaf Key or Stock Island specimens that
we have taken or seen is typical, and all represent a new taxon, herein
described:
Euphyes pilatka klotsi L. Miller, Harvey and J. Miller,
new subspecies
Male (Figures 1-2): Similar to $ of E. p. pilatka (Figures 5-6), but
differing in the following respects: upper forewing slightly redder and with
increased basal fuscous shading and with marginal fuscous border en-
croaching on median fulvous patch resulting in a less extensive fulvous area;
subapical spots usually prominent (these are generally coalesced with and
obliterated by the fulvous median area in nominate E. pilatka); hindwing
above with greatly reduced fulvous median shading; hindwing beneath
with ground color much darker fuscous than in nominate race.
Male genitalia (Figures 11-15) as illustrated. As with a number of
hesperiine species, the valvae are asymmetrical in E. pilatka with a great
deal of variation along the costal margin (Figures 11-18) which may be
dentate or smooth. The cucullus in the new subspecies, E. p. klotsi, is more
produced, whereas that of the nominate subspecies is rather blunt. The
setal and associated scale tufts along the costa and sacculus are consistent-
ly more pronounced and thicker in the new subspecies, with the setal patch
along the inner margin of the cucullus more extensive than in E. p. pilatka.
Length of forewing of Holotype: 8 19.6 mm.; those of the 43 & para-
types range from 18.0 to 20.4 mm., averaging 19.29 mm.
Female (Figures 3-4): Much darker above and below than 9 of p.
pilatka (Figures 7-10); no, or only a trace of, fulvous basal suffusion on
upper forewing of the present subspecies (most specimens of nominate E.
pilatka have strong fulvous suffusion nearly to the base of wing); subapical
forewing spots (occasionally only one of these present) always separate
from median fulvous spots from M3-Cu1 through Cu2-2A (these spots
usually coalesced by means of additional spots in M1-M2 and M2-M3 in
E. p. pilatka); upper hindwing with central area reduced to at most a dash
in Rs-M, (a broad diffuse fulvous area in nominate subspecies) and under
hindwing very much darker than in nominate subspecies.
Female genitalia (Figure 19) as illustrated, with a somewhat less
heavily sclerotized anterior part of the ductus bursae near where it joins
the bursa copulatrix and slightly differently shaped lamella antevaginalis
than nominate E. pilatka (Figure 20). The figures illustrate the two rather
similar morphological types which may be observed in this species, but
there as much variation in the degree of sclerotization of the ductus bursae
at the juncture of the bursa copulatrix within populations as between
demes. The ductus seminalis occurs on the lightly sclerotized portion of the
bursa copulatrix and just beyond the juncture with the ductus bursae.
Lengths of forewings of the 18 9 paratypes range from 19.6 to 23.3
mm., averaging 21.28 mm.
Described from 62 specimens, 44 males and 18 females, from the Lower
Florida Keys, Monroe Co., Florida.
HOLOTYPE & :-FLORIDA: Monroe Co.: Sugarloaf Key, T66S,
R27E, Sec. 23; 23.VI.1979 (D. J. Harvey); & genitalia preparation M-
3993-h (D. J. Harvey).
Florida Entomologist 68(2)
3 T 4
7 8
Figs. 1-10. Euphyes pilatka subspecies. 1-4: E. p. klotsi, new subspecies;
Holotype S, upper (1) and under (2) surfaces (Allyn Museum photos
020180-16/17); FLORIDA: Monroe Co.: Sugarloaf Key; Paratype 9,
upper (3) and under (4) surfaces; FLORIDA: Monroe Co.: Big Pine Key
(Allyn Museum photos 020180-18/19). 5-10: E. p. pilatka (W. H. Edwards);
5-6. S upper (5) and under (6) surfaces; FLORIDA: Sarasota Co.: vie.
Myakka Park (Allyn Museum photos 072580-11/12); 7-8, 9 upper (7)
and under (8) surfaces; FLORIDA: [Dade Co]: Royal Palm Park (Allyn
Museum photos 072580-13/14); 9-10, 9 upper (9) and under (10) sur-
faces; FLORIDA: "NE corner of Monroe Co." (Allyn Museum photos
072580-14/15).
PARATYPES:-all FLORIDA: Monroe Co.: 6 & 1 9, same locality
as Holotype, 22.VI.1979 (D. J. Harvey and J. Longino); 1 & 2 9, same
data and collector as Holotype; 1 S, Sugarloaf Key, 13.XI.1953 (C. P.
Kimball); 4 & 1 9, Sugarloaf Key, 11.IV.1975 (D. Oosting); 2 3, Sugar-
loaf Key, 28.IX.1980 (L. D. and J. Y. Miller); 1 3, Sugarloaf Key, ex
pupa on Mariscus, emerged 9.X.1980 (D. J. Harvey); 1 8, Stock Island,
1 2
326
June, 1985
Miller et al.: New subspecies of Euphyes
327
Fig. 11. & genitalia of Euphyes pilatka klotsi, new subspecies (genitalia
preparation M-3993-h [D. J. Harvey]). Note extensive associated setal and
scale tufts.
26.XII.1970 (T. S. Dickel); 1 S, Big Pine Key, 1-5.IV.1951 (L. J. Sanford);
2 $, Big Pine Key, 1-5.1.1952 (L. J. Sanford); 5 & 1 8, Big Pine Key,
1-5.II.1952 (L. J. Sanford); 3 & 1 9, Big Pine Key, 3-7.II.1952 (L. J.
Sanford); 1 9, Big Pine Key, 5-9.II.1952 (L. J. Sanford) ; 1 8, Big Pine
Key, 24-29.III.1952 (L. J. Sanford); 1 S, "entrance to lane leading from
paved road to Watson's Hammock," Big Pine Key, 17.11.1954 (L. Harris,
Jr.); 1 8 1 9, Big Pine Key, 30.XII.1977 (H. D. Baggett, Jr.) ; 1 & 1
9, Big Pine Key, 4.IV.1978 (F. D. Fee); 1 9, Big Pine Key, 4.IX.1978
(T. S. Dickel); 1 &, Big Pine Key, 16.III.1979 (F. D. Fee); 1 &, Big Pine
Key, 20.III.1979 (F. D. Fee); 1 9, Big Pine Key, 23.VI.1979 (D. J.
Harvey); 2 9, Big Pine Key, 24.IX.1979 (L. D. and J. Y. Miller); 1 a 1
9, Big Pine Key, 8.XII.1979 (D. S. Smith); 1 8 1 9, Big Pine Key, 10.-
III.1980 (F. D. Fee); 1 8 Big Pine Key, 29.VI.1980 (J. Weintraub); 4 &
1 9, Big Pine Key, 28.IX.1980 (D. J. Harvey, L. D. and J. Y. Miller);
1 S 1 9 Big Pine Key, 19.XII.1982 (J. Shuey).
Disposition of type-series: Holotype &, 3 & and 2 9 Paratypes in
Allyn Museum of Entomology, 15 S and 3 9 Paratypes in American
Museum of Natural History, 12 & and 5 9 Paratypes in the collection of
D. J. Harvey, 4 S and 3 9 Paratypes in the collection of F. D. Fee,
3 & and 1 9 Paratypes in the collection of D. F. Oosting, 1 & and
1 9 Paratypes in the collection of T. S. Dickel, 1 3 and 1 9 Paratypes
in the collection of D. S. Smith, 1 & and 1 9 Paratypes in the collection
Florida Entomologist 68(2)
June, 1985
12
16
13
118
15
Fig. 12-18. Range of variation in valvae of Euphyes pilatka. 12-15, E. p.
klotsi; 12, 13: FLORIDA: Monroe Co.: Sugarloaf Key [genitalic prep. M-
6574, M-6881]; 14, 15; FLORIDA: Monroe Co.: Big Pine Key [genitalic
prep. M-6586, M-3993-h]). 16-18, E. p. pilatka, all from FLORIDA: Sara-
sota (16, prep. M-3994-h), Monroe Co., Everglades National Park (17,
prep. M-6578), and Franklin Co., Appalachicola (18, prep. M-6584).
of H. D. Baggett, Jr., 1 S Paratype in the collection of C. P. Kimball,
1 8 Paratype in the collection of J. Weintraub and 1 $ and 1 ? Para-
types in the collection of J. Shuey.
Etymology: This subspecies is named in honor of Dr. A. B. Klots who
first indicated its possible subspecific distinctiveness.
We have not seen any specimens of E. pilatka from the Upper or Middle
Florida Keys, despite the fact that many of the islands such as Key Largo
and Lower Matecumbe Key have been rather well collected. Such negative
evidence does not prove that E. pilatka is absent from these Keys and
that the apparent disjunction of the range is real, but it does strongly
328
Miller et al.: New subspecies of Euphyes 329
,, i /,
" 1 / ^ -y.'^ *.- 4-
te k r i
S20
19 ) 'L 2
Fig. 19-20. 9 genitalia of E. pilatka. Note the more heavily sclerotized
and contorted base of the ductus bursae. 19, E. p. klotsi, new subspecies, Para-
type (genitalia prep. M-6575); FLORIDA: Monroe Co.: Sugarloaf Key; 20,
E. p. pilatka (genitalia prep. M-6579); FLORIDA: [Dade Co.]: Everglades
National Park.
suggest that this is so. The nominate subspecies is common on the mainland
of extreme southern Florida, and it seems likely that if E. pilatka occurred
in the Upper Keys, it would have been discovered by now. The reasons for
this apparent disjunction of the range of pilatka are obscure (there seems
to be a similar disjunction of the range of Hesperia meskei (W. H. Edwards),
according to W. W. McQuire, in litt.).
Specimens which we collected of E. pilatka klotsi were restricted usually
to small patches of sawgrass that were in low places in the pine woods
that cover much of Big Pine and Sugarloaf Keys. The adults seldom
strayed far from the sawgrass areas, and all of our specimens were taken
there. A search for immature stages was undertaken, and immediately we
Florida Entomologist 68 (2)
June, 1985
found bundles of sawgrass blades stitched together by larvae. Few living
larvae or pupae were found (although a number of empty pupal shells
were found); one pupa hatched into E. p. klotsi in Sarasota, thus confirming
the identification.
Additional collecting certainly needs to be done in northern Monroe
County to ascertain whether or not populations connecting the present sub-
species with E. p. pilatka exist. These intervening areas have been collected
thoroughly in the past, but perhaps the sawgrass patches have been over-
looked. We do know that such patches are not common from Big Pine Key
to the mainland, and those that we sampled did not have E. pilatka popula-
tions.
Females are readily distinguished from mainland E. pilatka by the re-
duced maculation on both wings. Statistical analysis was done on the per-
centage of forewing vein Cu2 that was covered by fulvous scales. E. p.
klotsi (10 specimens) averaged 0.3591 0.0095 fulvous, whereas E. p.
pilatka (25 specimens) showed a value of 0.5092 0.1018 fulvous; the
differences between the means of the populations was not significant at
the 95% level because of some rather dark examples of the mainland sub-
species. These differed from Keys specimens in other respects (more sub-
apical spots which were frequently coalesced with the median fulvous
patch and greater basal fulvous suffusion). Similar characteristics separate
males, through the differences are somewhat subtler, involving broader
dark margins of the forewings above, reduced fulvous on the upper hind-
wing and the fulvous of the upper surface being ruddier. The only character-
istic of these that is readily quantifiable involves the percentage of fulvous
and fuscous scaling ("a" and "b-a" in Figure 21) along forewing vein 2A,
and the results of statistical analyses for both E. p. pilatka and E. p. klotsi
were significant. Big Pine Key male specimens (25) averaged 0.3149
0.0046 fuscous along vein 2A, whereas mainland Florida male specimens
(41) gave a value of 0.2771 0.0043. These figures suggest that the two
populations are significantly different in this character.
The statistical analysis of male specimens was clouded somewhat by
two paratypes of E. p. klotsi collected by F. D. Fee on Big Pine Key which
more closely resembled nominate pilatka than did other examples of the
new subspecies. Genitalic examination of one of these specimens showed it
to be similar to those previously dissected from the area, although there
were some inconsistencies. These specimens were, however, included in the
type-series of E. p. klotsi.
Euphyes conspicua (W. H. Edwards), 1863
L. Miller and Brown (1981: 45) summarize the synonymy of this
species as of 1979-1980: two subspecies are recognized, E. c. conspicua and
E. c. buchholzi (Ehrlich and Gillham), 1951. Examination of many more
specimens, especially those in the Allyn Museum of Entomology from the
collection of F. H. and P. W. Chermock, suggests that the situation may
be more complicated than we first surmised.
Ehrlich and Gillham (1951: 188-189) characterize E. c. buchholzi as
being larger and more robust than nominate E. conspicua with a "tendency
towards obsolescence of the light markings on the underside of the primaries."
They further state, "This character is found only occasionally in eastern
330
Miller et al.: New subspecies of Euphyes
Fig. 21. Pattern of forewing of E. pilatka S showing distal fuscous
area and basal fulvous one. "a" is measured fulvous distance along vein
2A, "b" is total length of 2A: fuscous is denoted as "b-a".
specimens," and claim that "near topotypical conspicua" are identical with
eastern material in these characteristics.
Material from New England, New Jersey, Pennsylvania and especially
eastern Maryland is considerably darker (and usually smaller) than are
topotypical specimens from near Lansing, Michigan. These eastern speci-
mens have slightly to much reduced, but generally very prominent under-
forewing maculation. The males (except from Maryland, where they are
distinctly ochreous) are often slightly ruddier above than are those of
typical E. conspicua, and females have the pale markings of all wings
reduced in size, but more clearly delimited, than do topotypical specimens.
The late F. H. Chermock and his now-deceased son, Paul, noticed these
differences and accumulated a large series of specimens from the vicinity of
P--q
Florida, Entomologist 68 (2)
22 23 24 25
26 27 28 29
30 31
Fig. 22-31. Euphyes conspicua subspecies. 22-25: E. c. conspicua (W. H.
Edwards); 22-23, 8 upper (22) and under (23) surfaces; MICHIGAN:
Ingham Co.: Dansville Game Area (Allyn Museum photos 072580-17/18);
24-25, Y upper (24) and under (25) surfaces; same locality (Allyn Mu-
seum photos 072580-1A/2A). 26-31: E. c. orono (Scudder) ; 26-27, a upper
(26) and under (27) surfaces; MARYLAND: Baltimore Co.: Stevenson
(Allyn Museum photos 072580-9/10); 28-29, Y (dark morph) upper (28)
and under (29) surfaces; same locality (Allyn Museum photos $72580-5/6);
30-31, Y (light morph) upper (30) and under (31) surfaces; same locality
(Allyn Museum photos 072580-7/8).
Baltimore, Maryland (chiefly at Stevenson, Baltimore County), which
they intended to use as the basis for the description of a new subspecies
of E. conspicua. Paratypes of this putative taxon may have been distributed,
but the specimens are within the range of variation of eastern E. con-
spicua, though they do average a bit darker with pale markings tending
to be more ochraceous than specimens from Pennsylvania through New
England. Specimens of this population are shown in Figures 26-31. If
there was no available name for this eastern taxon, the proposed name
332
June, 1985
Miller et al.: New subspecies of Euphyes
333
Fig. 32. S genitalia of Euphyes c. conspicua (W. H. Edwards); MICHI-
GAN: Ingham Co., Dansville Game Area (genitalia prep. M-6659). Penis
is drawn in dorsal view at bottom of figure as well as in lateral view just
above it.
for the eastern specimens would have been in order, but Scudder (1872:
79) proposed the name Hedone orono for eastern E. conspicua. The type-
locality for E. orono was given simply as "northern states", and it is unclear
whether or not the specimens came from near the presentday town of Orono,
Maine, or if Scudder simply used another of the Indian names he was so
fond of employing, especially for hesperiids. The specimens from the eastern
seaboard are sufficiently different, including those from Maryland, as ex-
plained above, from topotypical E. conspicua from the Great Lakes area
(which are figured in Figures 22-25) to warrant the retention of the name
E. c. orono for these populations. There seems to be a slight disjunction in
the range of E. conspicua through western Pennsylvania and New York,
mapped by Shapiro (1971: 134; fig. 5), which is a larger "gap" than that
between populations of E. c. conspicua and E. c. buchholzi. The facies of
specimens reflects the greater differences between the eastern seaboard and
other populations as well.
Nevertheless, Ehrlich and Gillham (1951) described E. c. buchholzi
strictly from eastern Nebraskan specimens with the comment (1951: 189)
334 Florida Entomologist 68 (2) June, 1985
that "Wisconsin and Iowa specimens are intermediate between conspicua
and buchholzi, and should probably be designated as belonging to Atrytone
conspicua Cl. conspicua-buchholzi." Most of the material that we have
critically examined that might apply to this taxon has been from Iowa and
Wisconsin in this complex, and these specimens seem to conform more to
the concept of E. c. buchholzi than to that of conspicua. Until we see con-
siderably more material referring to E. c. buchholzi, we must refrain from
either synonymizing that name or confirming its identity. The male genitalia
(Figure 32) do not differ significantly between populations. Positions of
cornuti on the aedeagus are consistent.
Tentatively, we are accepting the distinctness of E. c. buchholzi and the
necessity of dividing the eastern population from the Great Lakes one.
This action leaves the following arrangement (numbers and letters refer
to the running checklist in L. Miller and Brown, 1981):
213. conspicua (W. H. Edwards), 1863
a. c. orono (Scudder), 1872
b. c. conspicua (W. H. Edwards), 1863
= pontiac (W. H. Edwards), 1863
c. c. buchholzi (Ehrlich and Gillham), 1951
ACKNOWLEDGMENTS
The following individuals and institutions loaned specimens that made
this study possible: Dr. J. M. Burns (National Museum of Natural
History), Dr. F. H. Rindge (American Museum of Natural History), Dr.
Chen W. Young (Carnegie Museum of Natural History), F. D. Fee (State
College, Pennsylvania), D. P. Boosting (Jenison, Michigan), Dr. D. Spencer-
Smith (Oxford, England), J. Weintraub (Cambridge, Massachusetts), J.
Shuey (Columbus, Ohio), H. D. Baggett, Jr. (Tampa, Florida) and T. S.
Dickel (Homestead, Florida). Dr. J. Longino, formerly of Sarasota, Florida,
helped collect some examples of E. p. klotsi during 1979. The late Dr. A. C.
Allyn (Allyn Museum of Entomology) helped prepare the figures, and S. R.
Steinhauser and Dr. W. Jenkins of the same institution read and commented
on the manuscript. The comments of the anonymous reviewers were valuable
and helpful.
REFERENCES CITED
BELL, E. L. 1941. Two new species of Hesperiidae from North America
(Lepidoptera). Ent. News 52: 163-169.
BROWN, F. M., AND L. D. MILLER. 1980. The types of the hesperiid butter-
flies named by William Henry Edwards. Part II, Hesperiidae:
Hesperiinae, section II. Trans. American Ent. Soc. 106: 43-88; ill.
BROWN, J. W., AND W. W. McGUIRE. 1983. A new subspecies of Euphyes
vestris (Boisduval) from southern California (Lepidoptera: Hes-
periidae). Trans. San Diego Soc. Nat. Hist. 20(3) : 57-68; ill.
EHRLICH, P. R., AND N. W. GILLHAM. 1951. A new Atrytone from Nebraska
(Lepidoptera: Hesperioidea). Ent. News 62: 188-189.
FREEMAN, H. A. 1975. A new species of Euphyes Scudder from Texas
(Hesperiidae). J. Lepid. Soc., 29(4) : 227-229.
KIMBALL, C. P. 1965. The Lepidoptera of Florida. Gainesville, Fla.: Florida
Dept. of Agric., Div. of Plant Industry. v + 363 pp.; ill.
LINDSEY, A. W. 1923. New North American Hesperiidae (Lepid.). Ent.
Miller et al.: New subspecies of Euphyes
News 34: 209-210.
MACNEILL, C. D. 1975. Family Hesperiidae, in Howe, W. H. (ed.), The
l.,,:l lfl;, of North America. Garden City, N. Y.: Doubleday and
Co. pp. 423-578.
MILLER, L. D., AND F. M. BROWN. 1981. A catalogue/checklist of the butter-
flies of America, north of Mexico. .i/l 1. Lepid. Soc. (2): iii-vii +
1-280.
MORRIS, A. 1974. Florida Place Names. Coral Gables, Florida: U. Miami
Press. 180 pp.
SCUDDER, S. H. 1872. A systematic revision of some of the American
butterflies; .. 4th Ann. Rept. Peabody Acad. Sci. [1871]: 24-83.
SHAPIRO, A. M., 1971. Postglacial biogeography and the distribution of
Poanes viator (Hesperiidae) and other marsh butterflies. J. Res.
Lepid., 9: 125-155; ill.
THREE NEW SPECIES OF HETEROMURUS
(ALLOSCOPUS) AND DESCRIPTIVE NOTES FOR
SPECIES OF THE SUBGENUS (COLLEMBOLA:
ENTOMOBRYIDAE)
JosE A. MARI MUTT
Department of Biology, University of Puerto Rico
Mayagiiez, Puerto Rico 00708
ABSTRACT
Three new species of Heteromuars (Alloscopus) are described: H. (A.)
thailandensis from Thailand, H. (A.) yosiius from Indonesia, and H. (A.)
deharvengi from Papua New Guinea. Details are added to the descriptions
of Heteromurus (Alloscopus) multispinatah Mari Mutt, H. (A.) tetracan-
thus B6rner and H. (A.) tenuicornis B6rner based on specimens from Papua
New Guinea and the Philippines. A key to the species of the subgenus is
included.
RESUME
Se described tres species nuevas de Heteromurus (Alloscopus) : H. (A.)
thailandensis de Tailandia, H. (A.) yosiius de Indonesia y H. (A.) dehar-
vengi de Papua Nueva Guinea. Se amplian las descripciones de Heteromurus
(Alloscopus) multispinatus Mari Mutt, H. (A.) tetracanthus Burner y H.
(A.) tenuicornis Birner en base a ejemplares de Papua Nueva Guinea y las
Islas Filipinas. Se incluye una clave para las species del subginero.
During a recent visit to the laboratory of Dr. Louis Deharveng, Uni-
versit6 Paul Sabatier, Toulouse, France, I gathered a large number of
Heteromurus (Alloscopus) collected by Dr. Deharveng and his colleagues
during expeditions to Thailand, the Philippines, Indonesia, and Papua New
Guinea. The material includes three new species described below and speci-
mens of the other three species described previously in Alloscopus.
The number given in parentheses after the collection data of each species
corresponds to a locality number assigned by Dr. Deharveng. The holotype
335
336 Florida Entomologist 68 (2) June, 1985
of Heteromurus (Alloscopus) deharvengi, n. sp., will be deposited in the
Australian National Insect Collection, Canberra. Specimens of H. (A.)
multispinatus, n. sp., listed without a locality number are on loan from the
Bishop Museum, Hawaii, and will be returned to that institution. All the
other specimens remain in my collection.
Morphological abbreviations used in this paper are as follows: Ant. 2,
Th. 2, Abd. 2, etc. = 2nd antennal segment, 2nd thoracic segment, 2nd
abdominal segment, etc.
The characters listed in the following paragraph are shared by all the
species of the subgenus and will be deleted from the descriptions.
Heteromurus (Alloscopus)
DIAGNOSIS. Antennae 5-segmented. Pigment absent or restricted to a
small eyepatch. Head with 13 S macrochaetae, a bothriotrix, and no macro-
chaetae posterior to macrochaeta Po. Inner pair of labral papillae large,
conelike. Setae of maxillary palp similar in length and shape. Behind post-
labial quadrangle (PLQ), near posterior margin of head, 2 + 2 ciliated setae
(Fig. 26). Macrochaetotaxy of Abd. 1 to Abd. 4 as in Fig. 13. Abd. 4 dor-
sally about 1.5x length of Abd. 3. Unguiculus with large outer tooth. One
smooth seta opposite tenent hair of metathoracic legs. Anterior margin of
collophore without scales, corpus of tenaculum with a median seta. Dental
spines present, mucronal spine absent.
Heteromurus (Alloscopus) thailandensis Mari Mutt, new species
Length to 1.7 mm. Head with small dark-red eyepatch but no eyes visible
in cleared specimens. Apex of Ant. 5 with slender pin seta (Fig. 6). Ar-
rangement of A and M macrochaetae as in Fig. 1; M3 present, R M1-A3/
A3-AO = 1.5 (1.2 2.0, n = 13). Length of postantennal organ about 2.4x
socket diameter of macrochaeta An2 (Fig. 4, 5). Outer labral papillae
rounded, with lateral conelike projections (Fig. 7, 8). Posterior portion of
labium internal to seta e with 1 ciliated seta, 1 smooth seta and 1-2 scales;
setae e, 11 and 12 smooth. Differentiated seta of outer labial papilla mounted
on a small protuberance (Fig. 10), its apex close to or slightly surpassing
apex of its papilla. Setae of PLQ smooth. Trochanteral organ with about
15 setae. Tibiotarsi without smooth setae. Inner margin of unguis with 1-2
unpaired teeth (Fig. 9), tenent hair accidentally missing in all specimens.
Macrochaetotaxy of Th. 2 and Th. 3 as in Fig. 2, 3. Lateral anal valves
without smooth setae. Dorsum of manubrium with 2 parallel rows of 4 + 4
smooth setae. Dens with 3-6 spines.
DIAGNOSIS: This species can be distinguished from all other members of
the subgenus by the shape of the outer labral papillae (cf. Fig. 7, 8, 27;
Mari Mutt 1978: 246, Fig. 16; Mari Mutt 1982: 90, Fig. 25).
HOLOTYPE: Thailand: Chiang Dao, base of plateau just north of the
cave, route Luang Por Sim, 17-XII-1980, on bark, L. Deharveng and A.
Gouze (16).
PARATYPES: Same data as holotype, on bark, soil, roots and leaf litter,
40 in alcohol and 12 on slides (2, 9, 11, 15, 16).
Heteromurus (Alloscopus) yosiius Mari Mutt, new species
Length to 1.8 mm. Eyes 1 + 1 surrounded by dark-red pigment. Apex
Mari Mutt: Three New Collembola
SA2
00 0 C
o' o 0 o o AA4
SA3 M2
0O
I 0 o MI
o o .. --- --- --.
M Po m2i
Pm
\ **
6
An2 0
0 A5
SM3
7
An2
5 An2
An2
Fig. 1-10. Heteromurus (Alloscopus) thailandensis, n. sp. 1. Macro-
chaetotaxy of anterior portion of head; A = anterior, M = median, An =
antennal. 2. Macrochaetotaxy of Th. 2; A = anterior, L = lateral, M =
median, Pm = posteromedian, PI = posterolateral. 3. Macrochaetotaxy of
Th. 3. 4-5. Postantennal organ and 2 adjacent An macrochaetae. 6. Apex
of Ant. 5. 7-8. Labral papillae. 9. Claws, arrow indicates position of op-
tional unpaired tooth. 10. Outer labial papilla.
337
338 Florida Entomologist 68 (2) June, 1985
of Ant. 5 without pin seta but with 2 long, apically hooked setae. Arrange-
ment of A and M head macrochaetae as in Fig. 11, M3 absent. R M1-A3/A3-
AO = 2.4 (n = 2: 1.9, 3.0). Length of postantennal organ about 2.8x socket
diameter of macrochaeta An2 (Fig. 15, 16). Outer labral papillae conelike,
as in H. (A.) multispinatus Mari Mutt (Fig. 27). Posterior portion of
labium internal to seta e with 1 ciliated seta, 1 smooth seta and 2-4 scales;
setae e and 1, smooth, L1 ciliated. Differentiated seta of outer labial
papilla mounted on a large protuberance (Fig. 12), its apex some distance
behind apex of its papilla or reaching apex. Setae of PLQ smooth. Tro-
chanteral organ with about 25 setae. Tibiotarsi without smooth setae. Inner
margin of unguis (Fig. 14) without unpaired teeth, tenent hair lanceolate.
Body macrochaetotaxy as in Fig. 13. Lateral anal valves with 0-1 smooth
seta. Male genital plate with about 26 smooth setae arranged in 2 poorly
defined concentric rows. Dorsum of manubrium with 2 parallel rows of
4 + 4 (5 + 5?) smooth setae. Dens with 6-10 spines.
DIAGNOSIS: The only other member of the subgenus with 4 macrochaetae
on the Pm region of Th. 2 is H. (A.) tetracanthus Bbrner. The key to the
species details the differences between these taxa.
HOLOTYPE: Indonesia: Bogor, Java, 1200m, X-1983, native collector (21).
PARATYPES: Same data as the holotype, 1 in alcohol and 1 on slide.
ETYMOLOGY: The species is named after Dr. Ryozo Yosii in recognition
of his numerous contributions to the taxonomy of Oriental Collembola.
Heteromurus (Alloscopus) deharvengi Mari Mutt, new species
Length to 1.4 mm. Without eyes and pigment. Apex of Ant. 5 without
hooked seta but with pin seta as in H. (A.) thailandensis and a short apically
rounded sensilla. Arrangement of A and M head macrochaetae as in Fig.
19; M3 present, R M1-A3/A3-AO = 1.3 (n = 3: 1.0, 1.2, 1.8). Postantennal
organ small, irregular, seen only on 1 side of 1 specimen. Outer labral papil-
lae as in H. (A.) multispinatus but apex sharply pointed. Posterior portion
of labium internal to seta e with 1 ciliated seta, 1 smooth seta and 2 scales;
setae e and 12 smooth, L1 smooth or ciliated. Differentiated seta of outer
labial papilla as in Fig. 21. Setae of PLQ smooth. Trochanteral organ with
about 17 setae. Tibiotarsi with 2 rows of smooth setae along inner margin
of segment and variable number of similar setae on anterior and exterior
margins. Inner margin of unguis without unpaired teeth (Fig. 20), tenent
hair lanceolate. Macrochaetotaxy of Th. 2 and Th. 3 as in Fig. 17, 18. Each
lateral anal valve with 2 smooth setae. Male genital plate with about 25
smooth setae arranged in 2 concentric rows. Dorsum of manubrium with
2 parallel rows of 4 + 4 smooth setae (Fig. 22). Dens with 3-5 spines.
HOLOTYPE: Papua New Guinea: Wau, route to Mt. Kaindi, 2100 m,
8-XI-1978, humus and mosses, L. Deharveng (72).
PARATYPES: Same data as holotype, 2 in alcohol and 1 on slide (71, 73,
74).
Heteromurus (Alloscopus) multispinatus MARI MUTT, 1982
This species was described from two specimens collected in Muller
Plateau, SE Papua New Guinea. The collections under study consists of
100 specimens from 12 localities spread across the main island of Papua
Mari Mutt: Three New Collembola
_AO
0 0
A3
U 0 MI
o A4 O A n2
'0
Fig. 11-16. Heteromurus (Alloscopus) yosiius, n. sp. 11. Macrochaetotaxy
of anterior portion of head, letters as in Fig. 1. 12. Outer labial papilla. 13.
Body macrochaetotaxy. 14. Claws. 15-16. Postantennal organ and eye.
o'
0o
0'
339
Q) I
0
Florida Entomologist 68 (2)
June, 1985
.0 AO o
S. 0 00 0A4
0o 0o A4
SM2 0 A5
00 0M3
22
Fig. 17-22. Heteromurus (Alloscopus) deharvengi, n. sp. 17. Macrochae-
totaxy of Th. 2, letters as in Fig. 2. 18. Macrochaetotaxy of Th. 3. 19. Macro-
chaetotaxy of anterior portion of head, letters as in Fig. 1. 20. Claws and
smooth setae of tibiotarsus. 21. Outer labial papilla. 22. Dorsum of manu-
brium and proximal portion of dentes.
340
Mari Mutt: Three New Collembola
341
New Guinea. The following remarks are based on a detailed study of 12
specimens from localities 69, 273 and 277.
Length to 2.3 mm. Eyes 1 + 1, sometimes surrounded by dark-red or
black pigment. Apex of Ant. 5 with slender pin seta and an apically round-
ed sensilla (Fig. 24). Arrangement of A and M macrochaetae as in Fig.
25; A5 and M3 present, R M1-A3/A3-AO = 1.0 (0.9 1.2, n = 10). Length
of postantennal organ about 2.6x socket diameter of macrochaeta An2.
Outer labral papillae conelike but not sharply pointed like inner papillae
(Fig. 27). Posterior portion of labium internal to seta e with 1 ciliated
seta, 2 smooth setae and 3-4 scales (Fig. 26); setae e and 12 smooth, 1.
smooth or ciliated. Trochanteral organ with 30-41 smooth setae. Inner
margin of unguis with pair of large basal teeth and 0-1 unpaired tooth.
Lateral anal valves with 0-1 smooth seta. Male genital plate with about
40 smooth setae arranged in 2-3 concentric rows. Dorsum of manubrium
with 2 rows of 3 + 3 or 4 + 4 smooth setae (Fig. 28). Dens with 27-55
spines arranged in 2 rows.
The trochanter is absent on 1 metathoracic leg of 1 specimen (Fig. 23).
The "femur" bears the setae of the trochanteral organ but their arrangement
is not that of a normal trochanter.
DIAGNOSIS: The presence of 2 rows of dental spines with up to 55
spines total separates this species from the other members of the subgenus,
which carry no more than 10 spines arranged always in a single row.
SPECIMENS EXAMINED: Papua New Guinea: Musgrave River, south of
Port Moresby, 6-XI-1978, L. Deharveng, 6 in alcohol and 2 on slides (23,
25). Wau, route to Mt. Kaindi, summit, 2400 m, 8-XI-1978, mosses, litter and
humus, L. Deharveng, 41 in alcohol and 8 on slides (68, 69, 70). Wau, Bull-
dog Rd., leaf litter, L. Deharveng, 18 on alcohol and 4 on slides (256, 262,
271, 273, 275, 277, 278). Finschaffen, 16-20-XII-1978, leaf litter, L. De-
harveng, 1 in alcohol and 1 on a slide (314). Tsenga, upper Jimmi Valley,
1200 m, 14-VII-1955, grass straw, J. L. Gressitt, 4 in alcohol and 2 on slides.
Swart Valley, Knagami, 19-XI-1958, moss, J. L. Gressitt, 1 on a slide.
North side of Mt. Gilure, 2500 m, 25-V-1961, malgi moss, M. and L. Gressitt,
2 on slides. Mt. Otto, 2500 m, 22-VI-1955, humus, J. L. Gressitt, 1 in alcohol
and 1 on a slide. Daulo Pass (Asaro-Chimb .. .), 2600 m, 14-VI-1955, moss
and humus, J. L. Gressitt, 1 on a slide. Mt. Kaindi, 2350 m, VIII-1977, litter,
3 in alcohol and 1 on a slide. Star Mountains, Sibil Valley, 1250 m, 15-20-X-
1961, litter, L. and S. Quate, 2 on slides, Mt. Wilhelm, 4260-4694 m, 24-X-
1975, P. Beron, 1 on a slide.
Heteromurus (Alloscopus) tetracanthus BORNER, 1906
This species was described originally from Java and has since been re-
corded from the Philippine island of Luzon, Malaysia, Singapore, India,
New Britain, Australia (Queensland), Samoa and Micronesia. Mari Mutt
(1978) suggested that the Philippine records of Gapud (1971) belong to
H. (A.) tenuicornis Bbrner and this opinion is supported by the present
study of numerous specimens from the islands of Luzon and Mindoro.
Yosii's (1959) records from Malaysia (Malaya) and Singapore are
doubtful because his specimens have a different chaetotaxy on Th. 2. Hetero-
murus (Alloscopus) deharvengi and H. (A.) thailandensis have the chaeto-
taxy of Yosii's specimens but only the former has smooth setae on the
Florida Entomologist 68 (2)
June, 1985
AO
0 A2
25 0 0 A4
0 0 0
A3
0 M2
0
0\
0MI
27
28
Fig. 23-28. Heteromurus (Alloscopus) multispinatus Mari Mutt. 23.
Abnormal and normal metathoracic legs, note different arrangement of tro-
chanteral organ setae. 24. Apex of Ant. 5. 25. Macrochaetotaxy of anterior
portion of head, letters as in Fig. 1. 26. Labium and setae along cephalic
groove, PLQ = postlabial quadrangle. 27. Labral papillae. 28. Dorsum of
manubrium and proximal portion of dentes, setae with arrows are absent
in some specimens.
342
Mari Mutt: Three New Collembola
An2
52 5
33 03
a4
5 .. 12
Fig. 29-33. Heteromurus (Alloscopus) tenuicornis Borner. 29-31. Claws,
arrow in Fig. 31 indicates position of occasional unpaired tooth. 32. Post-
antennal organ, eye, and 2 adjacent An macrochaetae. 33. Labial chaetotaxy;
a = anterior, E = external, L = lateral, smallcase for smooth setae, capitals
for ciliated setae. Note presence of a scale in position of L1.
343
Florida Entomologist 68 (2)
June, 1985
tibiotarsi. It is very likely that Yosii's specimens belong to H. deharvengi
or to a new species closely related to this one. The record from New Britain
(Yosii 1960) demands verification because the specimens are from Rabaul,
and 1 individual from Rabaul in the present collection belongs to H. (A.)
tenuicornis.
Postantennal organ (unrecorded previously for this species) bean-shaped,
small, its length about 1.1x socket diameter of macrochaeta An2. Head
macrochaeta A5 present, R M1-A3/A3-AO = 1.7 (n = 3: 1.60, 1.69, 1.74).
Posterior portion of labium internal to seta e with 1 ciliated seta, 2-3 smooth
setae and sometimes a small scale; setae e, 11 and 12 smooth. Inner margin
of ungues with 0-2 unpaired teeth.
DIAGNOSIS: The only other species of the subgenus with smooth setae
on the tibiotarsi is H. (A.) deharvengi, and its diagnosis separates it from
tetracanthus.
SPECIMENS EXAMINED: Papua New Guinea: Lae, 10m, P. Beron, 1 in
alcohol and 6 on slides.
Heteromurus (Alloscopus) tenuicornis BORNER, 1906
This species was described originally from Java and has since been re-
corded from Sumatra, the Philippine island of Luzon, Micronesia and Hawaii.
The following observations are based on specimens from the Philippine
Islands (Luzon and Mindoro) and Papua New Guinea (New Britain and
New Ireland).
Apex of Ant. 5 without pin seta, sometimes with a hooked seta and an
apically rounded papilla. Postantennal organ (unrecorded previously for
this species) bilobed, small, subequal in length to socket diameter of macro-
chaeta An2 (Fig. 32). Eyes 1 + 1 or absent. Head macrochaeta A5 present,
M3 absent. Mean of distance M1-A3/A3-AO = 3.0 (2.5 3.9, n = 11).
Posterior portion of labium internal to seta e with 1-2 ciliated setae, 0-1
smooth seta and 2 scales; seta e ciliated or smooth, L1 substituted by a
scale (Fig. 33), 12 smooth. Setae of PLQ smooth or ciliated. Second thoracic
segment with a posterolateral (P1) macrochaeta. Inner margin of unguis
with 0-2 unpaired teeth. Manubrium with variable number of smooth setae.
The specimens from the Philippine Islands can be separated into 2
groups. Individuals from localities 17, 18, 20, 26, 28, 20, 42 and 47 possess 2
ciliated setae on the posterior margin of the labium (Fig. 33); seta E, the
setae of the PLQ, and all other setae on the venter of the head are ciliated,
and there are none or 1 + 1 smooth setae on the dorsum of the manubrium.
Specimens from localities 5, 7, 21, 115, 118, 119 and 120 have only 1 ciliated
seta on the posterior portion of the labium; seta e, the setae of the PLQ
and all other setae on the venter of the head are smooth, and the dorsum
of the manubrium carries 2 rows of 4 + 4 smooth setae. Specimens of both
groups were found with 0-2 unpaired inner ungual teeth (Fig. 29-31).
DIAGNOSIS: Although different populations of this species exhibit con-
siderable variation in number of teeth on the inner margin of the unguis, and
in the chaetotaxy of labium, venter of head, and manubrium (see above),
this species can be recognized by the presence of 6 Th. 2 Pm macrochaetae,
labial seta L1 substituted by a scale, R M1-A3/A3-AO = 3.0 (2.5 or less in
the other species) and by the long and sharply pointed inner pair of ungual
teeth.
SPECIMENS EXAMINED: Philippines, Mindoro, Puerto Galera, nr. San
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