Variance in male mating success and female choice for persuasive courtship displays

Abstract

An important function of the courtship displays of male animals is to stimulate, or ‘persuade’, females to mate. While many studies of courtship success have shown that females choose stimulating males as partners, fewer have demonstrated that the most persuasive males in a population also enjoy the highest mating success (i.e. mate with the greatest numbers of partners). Such a relationship provides a stronger test of the hypothesis that male displays evolve by sexual selection via female choice. We tested this hypothesis in the laboratory using the North American plethodontid salamander,Desmognathus ocoee, in which females only elicit spermatophore deposition if rendered sexually responsive by male courtship. First, we determined variance among individual males in the numbers of females with which they mated across 35 encounters, in the absence of differences in partner encounter rates and direct intermale interactions. Second, we demonstrated that males with high ‘historical’ scores of mating success performed significantly higher frequencies of persuasive courtship displays, which provide tactile, chemical and visual stimulation to females. We conclude that sexual selection via female choice favours persuasive displays because they confer high mating success on the males that perform them at the highest frequencies.