Meeting Abstract
40.6 Sunday, Jan. 5 09:15 Integrating genetics, physiology, and ecology to understand the evolution of condition dependent sexual traits: an elemental approach GOOS, JM*; COTHRAN, RD; JEYASINGH, PD; Oklahoma State University; University of Pittsburgh; Oklahoma State University jared.goos@okstate.edu
Condition dependence of sexual traits may help explain why sexual traits are extremely variable in the face of directional selection and how these traits may convey valuable information of potential mates. Previous studies have demonstrated condition dependence by exposing individuals to different resource environments and observing responses in sexual traits. No studies, however, have directly measured male condition (i.e., the pool of material resources available to allocate to traits (including sexual traits) and its relationship to sexual trait expression. Moreover, since materials (i.e., nutrients derived from food) are likely to vary over space and time, it is critical that we examine condition across a variety of resource supply environments. Using Hyalella amphipods, in which males possess a sexually selected claw, we quantified the additive genetic variance in claw expression, and in the acquisition and allocation of carbon (C) and phosphorus (P), two important elements in both the growth and maintenance of sexual traits, in contrasting C and P supply environments. Our previous radioisotope studies have indicated greater variation in male assimilation physiology of both C and P throughout ontogeny than females, indicating that the variation observed in male sexual traits may be evident in condition as well. Here we discovered relationships between male sexual trait expression and condition. Specifically, male condition accurately predicts trait expression in low-quality environments, while this relationship is less reliable in high-quality environments. These results have important implications for sexual selection theory and the evolution of sexual traits as we examine the relationship between male condition and sexual trait expression at the most fundamental level of organization.
