Anuran call properties as reliable indicators of environmental suitability for reproduction

Abstract

The onset of animal breeding activity is often accompanied by auditory signals, typically produced by males, that indicate reproductive status to potential mates and competitors. Here, using male anuran advertisement calls as a case study, we present the novel hypothesis that characteristics of ectotherm auditory signals that are modulated by temperature may also serve as bioclimatic indicators of the suitability of proximal abiotic conditions for reproduction. According to this hypothesis, thermal constraints on signal characteristics, such as call rate and duration, may facilitate tracking of environmental conditions by females. Through integrative analysis of empirical ecological studies, we demonstrate how variation in call properties may influence female reproductive physiology and behavior. We then outline how this proposed mechanism may enable environmental tracking and phenological shifts with climate change, provide guidelines for experimentally testing this hypothesis, and discuss applications of findings from this research to conservation management for species of concern.