Female túngara frogs vary in commitment to mate choice

Mate choice studies most often examine female preferences based on population responses, thus potentially overlooking individual differences in behavior. Moreover, such studies typically use invariant stimulus conditions to infer preferences. By using population responses and static stimulus presentations, it is difficult to thoroughly understand the complexity of the mate choice process, including variation present between individuals. Here, we investigated phonotactic mate choice behavior in female túngara frogs (Physalaemus pustulosus) in response to temporally dynamic presentations of male advertisement calls. We tested females on repeated trials to examine individual differences and found considerable variation in the extent to which females update their mate choice decisions. Females in our study were bimodally distributed and thus broadly classified as either committed or uncommitted to an initial mate approach. We compared body condition measures of females differing behaviorally and determined that females with larger residual body masses were more committed to initial mate choices than less massive individuals, despite the fact that all females were in reproductive condition and field collected in amplexus. Our results suggest that anuran phonotaxis, once considered to be a highly stereotyped behavior, is more complex and variable than previously thought. Copyright 2009, Oxford University Press.