Within-individual variation in sexual displays: signal or noise?

Animal sexual displays are typically repeated over time and consist of components that are also repeated within a display, creating potential for within-individual variation in signal production. Across taxa, patterns of variation in and female preferences for temporal properties of signals are well documented, but data describing how within-individual variation functions in communication are scarce. Is within-individual variation itself a signal of male quality, or noise that obscures another signal encoded by a temporal pattern? In this study of Cope’s gray treefrog, Hyla chrysoscelis, we used synthetic advertisement calls to examine the function of within-individual variation in two signal traits: pulse rate, a signal of species identity, and call rate, a signal of male quality. We examined relationships between male body condition and coefficients of variation within males for both signal traits. We then measured female preferences for within-individual variation. Because treefrogs ...