Assessing acoustic signal variability and the potential for sexual selection and social recognition in boreal chorus frogs (Pseudacris maculata)

An important and necessary step in the analysis of any communication system involves quantitative descriptions of how signals vary at multiple levels of organization (e.g., species, populations, individuals). Such descriptions provide a basis for generating testable predictions about the functions of signals and their specific physical properties in different behavioral contexts. Here, we report results from acoustical and statistical analyses of the advertisement calls of the boreal chorus frog, Pseudacris maculata. In addition to characterizing measures of central tendency and dispersion for our study population, we assess how calls encode potentially relevant information in the contexts of sexual selection and social recognition. Specifically, we describe the relationships between call properties and both body size and condition, and relate these findings to predictions about female mate choice and male-male competition. We also make predictions about the shapes of female preference functions based on analyses of the patterns of within-individual variation in call properties. Findings from multivariate analyses of advertisement calls are used to generate testable predictions about the potential for these signals to function in social recognition. We also discuss our results in relation to wildlife conservation and relevant studies of geographic variation.