Cultural Entomology

Abstract

he long-range female-attracting songs and long tactual cerci °r crickets are components of a unique mating system, some aspects of which evidently trace to the earliest instances of copulation in the insect line and help explain changes leading to 'he current major groups of insects. Thus, none of the primitively wingless modern insects copulate, while all winged >d secondarily wingless insects do, the majority with the male mounting the female and in some way holding or forcing her. n primitively wingless insects, however, a sac or bulb containing the sperm (a spermatophore) is transferred indirectly to the female without direct copulation. Like crickets, some ol these particular primitively wingless insects possess prominent tactual cerci (e.g., Thysanura), used to guide the female during spermatophore transfer, as also in cockroaches and mayflies, n all insect groups of ancient origin that have prominent tactual cerci, transfer of the spermatophore is a luring act in which the female either mounts (winged and secondarily ngless forms) or stands beside the male (primitively wingless s). In some crickets, such as the field cricket genus Gryllus, copulatory act appears unique among all animals in being entirely luring, with no evidence of controlling force by the e at any stage. The female' is .ittraded initially by the longange calling song and then by the male's close-range courtship ;°g and probably the fluttering touches of his antennae 'g7). As in nearly all crickets, most close relatives of crickets, and most cockroaches and mayflies (the last aerially), the ale mounts (or flies above) the male in the copulatory act. PParently in correlation with the male field cricket having nimal ability to clasp the females genital parts, the Prnatophore is transferred quickly, in 15 to 90 s. The 'ermatophore is osmotically self-emptying, so that sperm lection occurs largely after the female dismounts from the In forms related to crickets, such as Tettigoniidac and fera, m which males have evolved terminal claspers on the nen, the tactual cerci have disappeared and copulation rnucn lengthier. In Caelifera the mating act has evolved c that the male mounts the female, though still reaching neath her to attach the genitalia; here, un l ike Tettigoniidae, ntennae have also become much shorter. Apparently S copulatory acts in insects have repeatedly evolved into acts involv ing s igni f ican t force, but the reverse does not seem to have happened. Groups of features related to the history of insect mating acts have significance for interpreting changes in diagnostic features of major groups of insects, including cerci, . in tennae, gcn i t a l i a , wing structure, long-range communication, and modes of pair formation. Distinctive morphological and behavioral features of crickets, especially those related to their methods of pair formation and mating behavior, make them a pivotal group in understanding insect evolution and phylogeny.