Meeting Abstract
Because social and sexual signals often influence fitness, they receive substantial energetic investment and can be sensitive to the energetic status of an individual (i.e., condition-dependent). Understanding whether signal expression and energetics are regulated by the same mechanisms and whether signal expression is energetically limited is crucial for understanding the evolution of these traits. In this study, we used surgical castration and testosterone replacement in adult male brown anoles (Anolis sagrei) to understand the regulation and energetics of the dewlap, a social and sexual signal of anole lizards. We separated male anoles from a wild population in The Bahamas into three treatment groups: 1) castration surgery and a blank implant (CAST), 2) castration surgery and a testosterone implant (CAST + T), or 3) sham surgery and a blank implant (CON). Lizards were released, recaptured after two months, and measured for dewlap size and color, wet mass of fat bodies, and body condition (i.e., residuals of mass on length). We found that dewlaps were larger and darker (lower saturation and brightness) in both CON and CAST+T males compared to CAST males. Males with endogenous or exogenous testosterone (CON and CAST+T) also stored significantly less fat than CAST males. However, neither fat mass nor body condition was significantly correlated with dewlap size or color within any treatment group. Though our results do not directly link dewlap expression to energetic state, they indicate that both energetics and dewlap expression are regulated by a common hormonal mechanism.
