To persuade or be persuaded: which sex controls mating in a plethodontid salamander?

AbstractIn the dynamic process of courtship, males often must perform behaviour patterns that function to persuade females that are initially unresponsive to mate. But, to what extent is the outcome of a sexual encounter determined by a male's persuasiveness versus a female's responsiveness? We addressed this question in three laboratory experiments using a plethodontid salamander, Desmognathus ocoee, for which persuasion by males appears to be obligatory. We found considerable variation in mating success among individuals of both sexes, indicating variation in both male persuasiveness and female responsiveness (Experiment 1). In addition, males of high persuasiveness mated more often than males of lower persuasiveness, regardless of the levels of responsiveness of the females that they encountered (Experiment 2). Finally, we found that males of high persuasiveness performed certain sexual behaviour patterns more frequently and more rapidly than males of lower persuasiveness (Experiment 3). Our results suggest that male D. ocoee of high persuasiveness can mate successfully even with unresponsive females, which may be especially choosy about which males they accept. Thus, those male behaviour patterns that increase female motivation to mate likely are targets of sexual selection by female choice. Whether females that mate with persuasive males enjoy increased fitness awaits further study.