Doctoral Dissertation Research: Endocrine Mediation of Alternative Reproductive Tactics in Anurans

University Of Oklahoma Norman Campus, Norman OK

Investigators

Abstract

Proposal 0308958 - Endocrine mediation of alternative reproductive tactics in anurans PIs: Rosemary Knapp and Christopher J. Leary Lay Summary Physiological mechanisms contributing to the expression of alternative male mating tactics have been studied most extensively in fishes and reptiles that typically advertise using visual signals. Less is known regarding processes regulating vocal signal production in anuran amphibians (frogs and toads), despite the pervasiveness of alternative tactics in this group. For example, male toads typically vocalize to attract mates, but some individuals adopt alternative non-calling "satellite" tactics. Satellite males characteristically remain in close proximity to calling males and attempt to intercept incoming females attracted to vocalizing individuals. Theory predicts that these plastic adult behavioral phenotypes should be subject to effects of hormones that mediate the expression of one behavior over the other. In anurans, it is thought that alternation between calling and non-calling behavior is related to a reciprocal interaction between circulating levels of the "stress" steroid hormone corticosterone and sex steroids (androgens) that is driven by depletion of energy reserves during vocalization. Preliminary data support a relationship between corticosterone levels and depletion of energy reserves during vocal bouts but indicate that alternation between calling and satellite behavior is independent of androgens. The proposed studies will test an alternative model to determine the physiological basis for male reproductive behavior in toads.