Aggressive Mimicry in Photuris Fireflies: Signal Repertoires by Femmes Fatales James E

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Aggressive Mimicry in Photuris Fireflies: Signal Repertoires their paLtternis at characteristic intervals. When a male receives an answer to his by Femmes Fatales signal he flies toward it and emits his pattern again. A flash-answer dialogue Abstract. Females of Photuris versicolor prey oni mnales of other species bv continues ior five to ten exchanges and ntiimnzickinig the flashi responises of thle prey's owni femniales. They adjust thleir ulntil the male reaches the female. Fig- responses accor-ding to the male pattern1, anzd attract male.s of folur species with itre 1 illustrates the mating signal codes distinictively different flashedl responses. The capabilities of the firefly brainl alrie of the species involved (5), and tabu- mizore comtplex tltila previously su.specte(d. The nuitnicry is quiite effective, andl lates the observed mimicry repertoires feniales seldomii answered mizore thani tell inales witholut catching one. observed. Two females were observed in natural Females of at least 12 species of left in situ for experimentationi. Experi- experiments" answering passingnmales Plhotutris fireflies are predators of male menilts could not follow a rigid protocol of both Photinus tan ytoxis and Photurii fireflies of the genera Photinults, Photutris, because of the variable conditions under congener, and a third female answered Pyractomena, and Roboputs. Evidence which the females were fouLnd. Also, a simulated Photinuis nzacdermno;ti pat- for this comes from observations of fe- since the experiments were conducted tern and was found to be already eating males eating (1) as well as capturing in the field, the females were continually a Plhotutris sp. A (6) male. (2, 3) the males. The females lure the inflLuenced by the signals of free-flying Eleven females answered the lnlac- males to them by mimicking the mating males in the area. (On seveni occasions dlerinotti simLllation appropriately and signials of the prey species' females. The experimental subjects interrupted exper- then answered the tanyWtoxis simulation males are then seized and devoured. iments involving simulated patterns by appropriately. This change required al- Although I have observed different Phlo- flashing appropr-iate answers to different terinig the length of their emissions as Downloaded from tlanis versicolor females capturing males patterns that were cemitted by passing well as flashing after each flash rather of four species, these observations do males.) A female, once located, was than only after the second, as niecessary not alone demonstrate the mimicry ver- first prescnted with an airtificial flash for macdermotti (Fig. 1). For example, satility of these females since (i) Pho- pattern simulating the signal of one of one female answered 11 consecutive tuiris species are difficult to identify and the prey species. After several responses miiacdermsSotti patterns with flashes 0.12 the behavior of different species could had been elicited, the pattern of another to 0.16 second in duration (at intervals http://science.sciencemag.org/ be attributed to a single one (4) and prey species was presented. Experiments of 8 to 10 seconds). On the first nine (ii) individual females might only be were terminated if a female failed to she flashed after each puLlse of each pat- capable of mimicking the signal of a respond to 15 to 20 pre.ertations. tcrn (7); she answered the next two single prey species, variation among the The species involved have a common correctly. She was then presented with females accounting for the inferred mul- general patterin of mating behavior. several 0.5-second flashes (tanytoxuis). tiple mimicry. I have been able to dem- Males fly about in their habitat emitting She did not answer the first seven, but onstrate by field observation and experi- their specics-specific flashinT patterni. on nLinmbers eight to ten responded with nmentation on individual P. versicolor Females flash answeTs from perches. a sihort flash. On the 11th she produced females that they do indeed have signal Timing elements of the emissions are ai dim glow after the flash, anid on the repertoires. important for recognition. Imnportant l 2th her flash length was 0.6 second on October 1, 2017 Females used for experimentation parameters in the miale pattcrnis are and the glow was held more than 9 sec- were feund by their flashed answers to flash number, rate. and duration, anid onds. She was then given the inacd1er- passin-g nmales or to penlight simulations in the female responise, flash length, and mlotti pattern, which she answered prop- of prey species' signals, and were on the the delay at which it occuLrs after the crly on the first presentation, but with ground or low vegetation. They were male pattern. Advertising males repeat anl intermediate flash length of 0.24 second (8) and no afterglow. Her next flash was 0.16 second in duration. In other words, she had immediately T I M E (S E C ) Fig. 1. Luminescent switched to the inacdernmotti response. signals of fireflies. Then, given a 0.5-second (tanytoxuts) 0 1 2 3 Response used by MACDERMOTTI MIALE predator is shown flash, she answered it with the appropri- FEMALE IF- ate long answer, a 0.6-second flash. In M IUl IC a. 9% below female an- I1 swer it mimics. Ver- both cases she had made a rapid adjust- TANYTOXUS MALE tical bars at right ment on the basis of the duration of the F Et1ALE indicate observed in- stimulus dividual repertoires; flash. Females sometimes re- MIMIC II lI 20% N is the number of sponded immediately to pattern changes. SPECIES A MALE A females exhibiting but occasionally as many as 15 presenta- F EMALE the repertoire. Cap- tions had to be made before a response ture rates (percent- to the new signal could be elicited. MIMIC I 54% ages) are adjacent to prey species. The Six other females were given the sim- CONGENER MALE I I I I.I flash rate of the ulated tan ytoxius pattern first and then FEMALE I ? I I I I I conige,ier female is after one to eight presentations re- MIMIC I ? I I I a I il 4% variable, and the sponded to the 7nacdermriotti pattern. specific nature of One would not answer the the coding is un- macdermnotti VERSICOLOt MALE hII pattern and one always (N = 15) flashed (PREDATOR FEMALE a N = 17 4 3 2 known (see text). - I I I after both pulses of the pattern. Fe- * - - - I 452 SCIENCE, VOL. 187 males occasionally stopped answering anism by the flashes of a passing con- 5. The mating signals of prey species are dis- cussed in more detail in J. E. Lloyd, Univ. any pattern or flew away, and those gener male could immediately put the Mich. Muts. Zool. Misc. Publ. No. 130 (1966), tested undoubtedly differed with respect female into the aggressive mimicry pp. 1-95; Fla. Entomol. 52, 29 (1969). role. 6. This Photuris is apparently a new species. to age, condition of ovaries, number of These observations indicate that the ca- Revisional studies and a Latin binomen will be reported at a latcr date (J. E. Lloyd, in successful predations, exposure to pabilities of the firefly brain are more preparation). flashes of foreign males (kinds and complex than hitherto suspected. 7. These interposed flashes were occasionally observed during actual predation of this species numbers), and genetic makeup. JAMES E. LLOYI) on macdermotti (2) and could be eliminstmd Apparently the mimicry is not per- Department of Entomology, from the responses of some females when the stimulus patterns were spaced at intervals fect, although comparative figures can- University of Florida, of 8 to 10 seconds. not be given since attraction rates for Gainesville 32611 8. Both 0.16 and 0.24 second are within the range of macdermotti flash responses. The conspecific interactions are unknown. 0.24-second flash was intermediate only with One female captured the 12th mnacder- References and Notes respect to the responses this female emitted. 9. J. E. Lloyd, Entomol. News 79, 265 (1968). milothi male she answered. Another an- 1. J. E. Lloyd, Coleopt. Bull. 27, 91 (1973); L. L. Buschman, ibid. 28, 27 (1974). 10. I thank E. G. Farnworth and R. S. Lloyd swered 20 congener males, and then 2. J. E. Lloyd, Science 149, 653 (1965). for assistance in the field; T. J. Walker for helpful discussion, comments on the manu- moved to a different perch several me- 3. E. G. Farnworth, thesis, University of Florida script, and the loan of photographic equip- (1973). ment; A. Owens for photographic technical ters away and answered more than 20 4. Phottiris l ersicolor is a complex of several assistance; and the National Science Founda- additional males before she captured morphologically similar species which are tion (grant GB 7407) for financial assistance. widely distributed in the eastern and central Florida Agricultural Experiment Station Jotir- one. Another female caught the 21st United States. Extensive field investigations nal indicate that probably only one species is Series No. 5447. congener male that she was observed to present in Gainesville. 16 August 1974 answer. Capture rates were higher for prey belonging to other species: on five occasions I observed the demise of Downloaded from Phottiris A males; two females captured Erythrocytes in Human Muscular Dystrophy the first male answered, one caught the second, one the tenth, and one female The observations reported by Mathe- also with abnormal erythrocyte mor- got the 11th, although she had seized son and Howland (1) appeared to fill phology described in murine muscular the seventh male and it had escaped. the need for a simple and reliable dystrophy (4). Two other females captured the fifth method for detecting heterozygous car- On the basis of these reports we http://science.sciencemag.org/ lanytoxius males that they answered. riers of Duchenne muscular dystrophy studied the erythrocyte morphology in What is the evolutionary origin of the (DMD). Dramatic surface deformation five individuals with DMD, three oblig- false signals? Two independent sources of erythrocytes in scanning electron mi- atory carriers, and two normal controls. are suggested. The flashed responses to crographs was observed by these au- The methodology was identical to that Photuiris A, Photinus tanytoxus, and thors in both DMD patients and hetero- utilized by Matheson and Howland. Photinus mnacdermotti males appear to zygous carriers. This observation was Table 1 summarizes our findings and be similar in delay timing to the preda- consistent with previous results indicat- the data of these authors. Only one of tor's own mating responses. False sig- ing possible abnormalities in cation our five DMD patients had a percentage nals could have been derived originally transport (2), fatty acid patterns (3), of distorted erythrocytes falling just out- from mating responses and subsequently and sphingomyelin levels (3) in eryth- side the normal range. All carriers dem- on October 1, 2017 modified. Responses to the flashes of rocyte membranes in human DMD, and onstrated normal values. In addition, Photuiris congener males are similar to erythrocytes from DMD patients and the flashes that the predaceous females, obligatory carriers also exhibited nor- and those of many other Photuris spe- Table 1. Comparison of results obtained by mal morphology in routine peripheral Miale et al. (this comment) with results re- cies, commonly emit when they walk, ported by Matheson and Howland (1). Dis- blood smears stained with Wright's solu- land, or take flight (9). These "locomo- torted red blood cells are abbreviated Dist. tion, normal osmotic fragility, and nor- tion" flashes would need little if any RBC's. mal resistance to peroxide hemolysis. modification to attract some congener In summary, our data do not support Miale et al. Mathesonhowlandand males. (The flashes of the congener fe- Howland the adequacy of scanning electron mi- male, unlike those of other species, do Dist. RBC's croscopic analysis of erythrocytes for not bear a specific relation to each flash Sex Age RBC's Sex Age Dist. the detection of heterozygous carriers of of the male.) I am able to attract about (%) (%) DMD. one male in ten to the 0.08-second Normal controls T. D. MIALE, JAIME L. FRIAS flashes of a free-running oscillator with M 32 0 M 43 3.4 DANIEL L. LAWSON a period like that of the males. I once F 38 1 M 45 3.3 Depart,inent of Pediatrics, College of M 36 7.4 observed a lycosid spider eating a con- F 32 4.0 Medicine, University of Florida. gener male that continued to emit his F 20 3.2 Gainesville 32610 rhythmic pattern; two additional con- Obligator y carriers References genier males were attracted to the flashes F 42 6 F 32 35.1 of the captive, and were also seized by F 39 5 F 37 39.9 1. D. W. Matheson and J. L. Howland, Science F 37 0 F 32 34.0 184, 165 (1974). the spider. I offer this not as an example 2. J. L. Probstfield, Y. Wang, A. H. L. From, of a tool-using spider, for I doubt that DMD patients Proc. Soc. Exp. Biot. Med. 141, 479 (1972). M 13 5 M 12 65.4 3. D. Kunze, G. Reichmann, E. Egger, G. Leusch- it is repeated with regularity, but as an M 11 0 M 15 98.4 ner, H. Eckhardt, Clin. Chim. Acta 43, 333 indication of how a physiologically in- M 10 14 (1973). 0 M 40.6 4. P. F. Morse and J. L. Howland, Nature appropriate but trophically fortuitous M 9 24 M 1 20.6 (Lond.) 245, 156 (1973). M 6 7 activation of the locomotion flash mech- 12 August 1974 7 FEBRUARY 1975 453 Aggressive Mimicry in Photuris Fireflies: Signal Repertoires by Femmes Fatales James E. Lloyd

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