Calling behavior and the capacity for sustained locomotory exercise in the Gray Treefrog (Hyla versicolor)

摘要

Vocal advertisement by male anurans can make considerable demands on an individual's energetic reserves and innate physiological resources. In this study, we tested for a relationship between calling and locomotory performance in male Gray Treefrogs, Hyla versicolor. Male vocal activity was monitored in choruses assembled in an artificial pond and call duration and pulse effort used as calling performance metrics. Swimming distance served as our measure of locomotory performance. When males were compared within experimental choruses, there was no tendency for the male that produced the longest calls to swim further than the male that produced the shortest calls. Rather, the opposite was true. When these same males were ranked based on their pulse effort, we found that the male with superior calling performance also performed better in the swimming test than the male that gave fewer total pulses. There was no significant relationship between male condition (weight relative to length) and either calling or swimming performance. We hypothesize that pulse effort, which shows more stability within males under dynamic acoustic situations in choruses than call duration, may better reflect limitations of the cardiovascular and respiratory system than does call duration.