Meeting Abstract

37.1  Thursday, Jan. 5  Approximate Bayesian analysis of sire precedence reveals first-male advantage in the brown anole lizard (Anolis sagrei) DURYEA, MC*; KERN, AD; COX, RM; CALSBEEK, RG; Dartmouth College; Rutgers University; University of Virginia; Dartmouth College duryea@dartmouth.edu

Studies of the effects of mating order, classically analyzed as the proportional paternity of the second male (P2), have given us important insights on the relative effects of postcopulatory male-male competition and female choice on sexual selection. However, these patterns are often difficult to analyze because both distributions of offspring number and proportional paternities are not normally distributed. Here, we overcome these difficulties by developing an approximate Bayesian model to analyze the effects of male mate order in the brown anole lizard, Anolis sagrei. The model is robust to relatively small samples sizes and is useful for studying mate order effects in a variety of systems. We applied the model to paternity results from a laboratory mating experiment in which we allowed female anoles to mate sequentially with two males. We find a marked first male advantage, with first males siring 75% of the offspring on average. We also show that second males are more likely to sire offspring when significantly larger than the first male. We discuss our results in terms of the implications both for postcopulatory sexual selection in this species, and for future analyses of paternity order in general.