Male within-individual variability in a sexual signal component and its impact on female choice
Abstract
A growing body of literature deals with the influence of physical or social environments on signal components over long time periods. Surprisingly, variations of signal quality over minutes or hours are less studied although most of the behavioral decisions of the receiver are taken at this time scale. Despite potentially strong implications on theoretical developments linked to sexual selection and communication, within-individual variability in a signal component and its possible consequence on accuracy of female choice has never been thoroughly investigated. Focusing on call dominant frequency (DF) in the European tree frog, Hyla arborea, we showed that frequency variability is due to a warm-up effect on the beginning of the call sequence but not to an exhaustion effect at the end of the sequence. Nevertheless, the great majority of male within-variability at the night scale is due to sudden discontinuities with independent temporal patterns from one individual to another. Secondly, we simulated female mate choice decisions with simple rules based on DF. Within-individual variability in DF the proportion of beneficial choice decreases up to 30% in the worst case. In addition, to overcome these temporary variations in male signal, we emphasize a weak advantage supplied by increasing sampling duration. The costs of being selective are assumed to increase with time sampling. We suggest that females may benefit from assessing several signal components simultaneously in short samples instead of disproportionately increasing sampling duration.
