MISCELLANEOUS PUBLICATIONS MUSEUM OF ZOOLOGY, UNIVERSITY OF MICHIGAN, NO. 130 Studies on the Flash Communication System in Photinus Fireflies BY JAMES E. LLOYD Museum of Zoology, University of Michigan ANN ARBOR MUSEUM OF ZOOLOGY, UNIVERSITY OF MICHIGAN NOVEMBER 25, 1966 MISCELLANEOUS PUBLICATIONS MUSEUM OF ZOOLOGY, UNIVERSITY OF MICHIGAN The publications of the Museum of Zoology, University of Michigan, consist of two series-the Occasional Papers and the Miscellaneous Publications. Both series were founded by Dr. Bryant Walker, Mr. Bradshaw H. Swales, and Dr. W. W. Newcomb. The Occasional Papers, publication of which was begun in 1913, serve as a medium for original studies based principally upon the collections in the Museum. They are issued separately. When a sufficient number of pages has been printed to make a volume, a title page, table of contents, and an index are supplied to libraries and individuals on the mailing list for the series. 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(1932) 64 pp., 3 pls., 1 fig., 1 map ................................... $0.75 No. A review of the dragonflies of the genera Neurocordulia and Platycordulia. By FRANCISBYERS. (1937) 36 pp., 8 pls., 4 maps ...................... $0.50 No. The crane flies (Tipulidae) of the George Reserve, Michigan. By J. SPEED ROGERS.(1942) I28 pp., 8 pls., 1 map ................................. $1.25 No. The ecology of the Orthoptera and Dermaptera of the George Reserve, Michigan. By IRVINGJ. CANTRALL.(1943) 182 pp., 10 pls., 2 maps ........ $1.50 No. Monograph of the family Mordellidae (Coleoptera) of North America, north of Mexico. By EMILLILJEBLAD. (1945) 229 pp., 7 pls. .............. $2.00 (Continued on back cover) XIISCELL.-\NEOUS PUBLICATIONS MUSEUM OF ZOOLOGY, UNIVERSITY OF MICHIGAK, NO. 130 Studies on the Flash Cominunication System in Photinus Fireflies JAMES E. LLOYI) ~lllrst.z~nzof Zoology, Univcls~tyof Micl~ignll ANN ARBOR AIUSEUM OF ZOOLOGY, UKIVERSITY OF MICHIGXN NOVEMBER 25. 1966 011 hito ni akali wo nlisuru hotaru kana Tlle firefly Gives light To its pursuer CONTENTS Accoui~tsof Species ........... Tlrc GCII~ISPlrol~trus .......... 1)ivision I ........... 1)ivision I1 ............ The pyruli.\ group ........ The pu?~cl~tlntusgroul) . l'llc ron.tui~g~ti~~rrisgro~cl) . '1'11~ cc~-tlet~\group ........ Conclusions ...................................................... 65 I)ISCUSSION ............................................................... 6.5 Evolutionary Origi~~of 1;l;tshetl Sign;tls ............................... 66 I-ficiency in Flasll (:o~rrcnrc~~it;ttio~r..................................... ti0 1;RONTISPIFCE OPPOSITI; PAGE 5 I:IGUI<ES IN TEXl I~I(;IIKE 1'Ac.I . I . Loc;rlities visitetl tlur.ing i~lvcstig;~tion.................................... 6 2 . Oscilloscope ti;rccs c~frccortlc:l fl;~\l~c\................................... 9 3 . I)ist~.il~utionof I'lrolirrrr.\ i~rSol-tli Anier-ica ............................ IS .I . I)istril)r~tion of 1'lrotirrrc.s 1)ivisiolr I .................................. 14 5 . I)istril)utio~~of IJlrolirrrr.\ cooki (;I-cen ................................. li (i. l)islril~~~tionol I'lroli~rtrc ~~rorgirrelltr.\LeC:olrte ........................ If; i . 1)istril)ut ion of I'lroli171r.\ crrrlntr~s(;reen ........................ I8 8. I)istril)utio~~of IJlrt~li~rrrs/loritln?rrr.\ Fa11 ............................ I!) $1. I)iitril~utio~iof I'lrolirrr~\ .\rrbtrlo.\~1.5 (;recrl ............................. 21 10 . 1)istl il~utionc~f I'ltolrrrr~.~ /)grcrli\ (Lit>~~a;.l~s)............................... 23 I1 . l)i.trilj~ction of I1lro/irrrrc nrr.\fr~itli.s (;rec:i .............................. 25 12. IIisr~il~ution01 IJlroIirrrr.\ .\~irrlillnrrs (%.I\) ............................... 2;i 13. 1)iirl-il)r~tio~iof' Plrolir~rr\IJI~III~~, yi (;rec~r ............................... 28 14 . I)islril)utiot~ of Plroliriri\ ,/~r~frc.lulrrlu.s1. :<.trlrre ............................ 30 15. l)istril)~~tio~rof I'lrt~li?rrr\ lc.rrrric.ir~r/rr.\(;~-cclr ........................... 31 I(i . l)ist~il)~~tio~rol' I'lrr~lr~rtr.~ rrr111~,- nlrrr L.e(.ontc ............................. 32 li . I)ist~.il)uric~~rof I'lrolirrtr. r~olIrr.\l~cr~r.~colrll~lc\ ............................ 34 IS . I)i\lril)utio~~of I'lrt~lirtrrr grrtrrrrlttlri.\ 1;:iII ............................. :I(; I!) . I)istt-il)l~titrnol' IJlrolirrt~.\tli~~ri\.\-rr.\ I.c(.o~rte ............................ 3S 20 . I)istril)~~tio~r01' I'ltolirr~rc irrtlitlri.\ (I.e<.o~rtc) ............................. 39 ?I . I)i?ll.il)ution ol I'irolrrrrr.\ lirtec.lIrr.\ I.e<.onlc ................................ 40 22 . I)isl~.il~ulii~~rol l'lr~lirrrr~ igr~ilrr.\ F:111 ................................. 41 23 . I)ist~il111 tioti of 1'lrolirrrr.c r c~rr.~crrr~rrirrc.~r.\COIII[, !c\ ....................... I? 24 . I)islril, ution of I'lreili~rrr.\ torr.\irrrili\ coml, lc\ ............................ 45 25 . 1)istr il~~~tior>of I'lrr~lirr trs ctr~oIirrrr\(;reell ............................... 47 2ii. 1)istl il)ulic~nof IJlrolirrrc.\ rtrrIf.rr.\ I.e(.o~~rc........................... 1IS 27 . I)iagl. ;IIII of st;rgei ill e\olrltic~lrol II:lsh signals ........................... (is 28 . I.'lasll.l~at~c~~tis;illtl Sc~n;~lcrcs~~o~~scs in I'lrolirrrrs .......................... 74 20 . Rcl;~rionslripof Il.~~l~-p.~ttc~.ni~~tc~v;~l to tc~riperaturc .................... ?.i., - .I0 . I<cl.~rio~~sliil,of fr111;ile re .; l1o11sc tlcl:lv ro tclrrl, cr.ltrlre ..................... i(i FRONTISPIECE Fl;~shcsant1 flight l);\tlls of m;ilc.s of sc\.c.ral dill'c.rcnt species ;IS they \tvoultl appear it1 a tilnc-lapse pllotogl.np11. .\rro~vsindicatc clircctio~~of flight. The spccies illustrated arc not ;ill sympntric. (1) 1'. r,otlsitrlili.\ (slon. pr~lse).(2) P. hri?nlt.~i,(3) P. rotisitt~ilis(fast pulsr) ant1 P. cnt.oli~/trs,(I) P. coll~r.rlr.nns,(5) I-'. r?,nr.ginc~lllts,(6) P. co?lsntigltinetts, (7) P. ig?~it~r.~,(8) P. ])?wr/i.\. ;11i(1(9) 1'. gra~tilfltt~.~. STUDIES ON THE FLASH COMMUNICATION SYSTEM IN PHOTINUS FIREFLIES" THE FIRST indication of human awareness of the function of light pro- duction in fireflies is found in a legend from India of cobras attracting fire flies to glowing stones (Harvey, 1957). The function of flashing as a mating adaptation was established early in the twentieth century largely through the studies of McDermott (1911-1917). During this period the flashes of males of several species and the response flashes of females of a few species were described, and the role of species-specific flash signals in reproductive isolation was demonstrated. In 1951, Barber, through observations of male flash-patterns, recognized several cryptic species in the genus Photurls. Although numerous recent studies have dealt with the physiology and biochemistry of firefly luminescence, only five have been concerned with the communicative function (Schwalb, 1961; Kaufmann, 1965; Lloyd, 19640, 1965n, 1965b). There have been no studies or theoretical discussions cotlsidering the general biological and physical factors governing the func- tioning and evolution of communication in fireflies. In spite of a volun~ino~~sliterature on American fireflies, the signals of most described species are unknown. The presumed functioning in reproductive isolation of the various parameters of the flash signal sys- tem, such as color and flash rate, is mentioned frequently in textbooks, not because the significance of these parameters has been demonstrated, but because variations among some species have been observed. The purpose of this study is to establish a founclation of general knowl- edge on firefly mating behavior; such general information should pinpoint species best suited for studies on the role of flash signals in reproductive isolation. The approach