Reproductive Biology of Cyphoderris strepitans: Copulatory Behavior and the Effect of Nuptual Feeding on Male Acoustic Activity

Abstract

Cyphoderris strepitans is a relic species of the Haglidae, an ancient group abundant during the Triassic and thought to have given rise to the modern crickets and katydids. C. strepitans occurs in disjunct 'pockets' only in the mountains of Wyoming and Colorado and little is known of its role in the ecology of these sensitive areas. Several features of this animals behavior are of interest to the evolutionary biologist. The mating period of C. strepitans occupies a very narrow time window of approximately 1 month and under ideal weather conditions most mating can take place within a period of several weeks. Males becore acoustically active very early in the spring (early May) and are able to stridulate at temperatures below 0° C (Dodson et al 1983). In addition to providing females with a spermatophore at mating, males also provision females with a nuptial gift. This food gift takes the form of the male's fleshy matathorasic wings; females feed on the wing material, and resultant flow of heamolymph, while in copula. The mating behavior of C. strepitans has not previously been adequately described and thus it was the first objective of this study to quantify the specific behaviors of the copulatory sequence. The environmental conditions under which males stridulate are extremely harsh and calling likely represents a physiologically costly endeavor. In a previous study (Sakaluk et al 1987) we hypothesized that non-virgin males, having invested in both a spermatophore and nuptial provisioning and thus lost a significant energy reserve, should be limited in their ability to sustain calling in a demanding environmnent. This should result in reduced attraction of females and consequently reduced remating success. The results of our 1986 study were inconclusive although significant differences between groups were noted (Sakaluk et al 1987). Our second objective was to retest this hypothesis using more sensitive techniques.