Temporal integration and binaural processing of acoustic information in Cope’s gray treefrogs (Hyla chrysoscelis)

The processing of acoustic signals enables animals to extract information and generate behavioral responses. Sexual selection exerts different evolutionary pressures on the sexes, shaping their sensory mechanisms to adapt to the appropriate strategy during communication. Cope’s gray treefrogs (Hyla chrysoscelis) are acoustically communicating amphibians in which both sexes perceive the same advertisement calls produced by the males to respond differentially to sex dependent tasks such as male- male aggressive interactions and female mate choice decision making. We explore two major acoustic sensory processing mechanisms, temporal integration and binaural processing, in male and female H. chrysoscelis. In the first chapter, we investigated how males and females use different temporal integration strategies for conspecific recognition. We hypothesized that the males would temporally integrate faster than the females at the expense of accuracy. We used stimuli containing combinations of conspecific and heterospecific call elements and conducted playback experiments to measure aggressive response from the males and phonotaxis decision-making in females. We found that the males are more permissive than the females and needed fewer pulses to reach decision-making thresholds. In the second chapter, we investigated how female frogs are temporally integrating conflicting directional information for sound localization using stimuli with leading and lagging pulses. We found evidence for our hypothesis that the females make decisions by integrating the majority of leading pulses. In the third chapter, we investigated how male and female H. chrysoscelis generate Binaural Interaction Components (BIC) by processing binaural cues such as interaural time (ITD) and level (ILD) differences. We found that ITDs significantly affect BIC latencies and that males exhibit shorter BIC latencies than females. Together, these results demonstrate how different reproductive costs and sexual dimorphism influence the auditory processing and decision-making of male and female H. chrysoscelis.