Meeting Abstract

14.1  Friday, Jan. 4  Sexual conflict during mating in red-sided garter snakes as evidenced by genital manipulation FRIESEN, C.R.*; MASON, R.T.; UHRIG, E.J.; BRENNAN, P.L.; Oregon State University; Oregon State Univeristy; Oregon State Univeristy; Univ. of Massachusetts at Amherst friesenc@science.oregonstate.edu

Sexual conflict occurs when the evolutionary interests of females and males are divergent. Sex-differences in optimal copulation duration can be a source of conflict. Males may evolve mechanisms to prevent females from remating to ensure their reproductive success, while females may otherwise benefit from mating again with a different male. Increased copulation duration may be advantageous for males as it delays female remating. Males of many species actively guard females to prevent them from remating, and in some cases males produce copulatory plugs to prevent remating. This conflict may be especially onerous to a female if precopulatory choice is limited at the time of her first mating. Male red-sided garter snakes (Thamnophis sirtalis parietalis) produce a gelatinous copulatory plug during mating that occludes the opening of the female reproductive tract for approximately two days. The size of the plug is influenced by the copulation duration. We experimentally tested the contribution of male and female control over copulation duration. We ablated the largest basal spine on the male’s hemipene and found a reduction in copulation duration and an increase in the variation of plug mass. Further we anesthetized the female’s cloaca and found copulation duration increased in this treatment group as well. This suggests that males benefit from increased copulation duration while females actively try to reduce copulation duration. Therefore, sexual conflict is manifest in divergent copulation duration optima for males and females.