Sarah Smith

Publication Date


Document Type

Honors Project

Degree Name

Bachelor of Arts




Lisa A. Mangiamele


Mutlimodal, Signaling, Frogs, Androgens, Frogs-Behavior, Androgens-Receptors, Testosterone-Receptors, Sexual selection in animals, Display behavior in animals


Sexual selection has generated a variety of elaborate displays that require the coordination of the nervous and muscular systems. One way individuals can precisely control these reproductive behaviors is through androgenic hormones, such as testosterone, that act on androgen receptors (ARs) in the brain, spinal cord, and muscles. Increasing the number of ARs may allow for selective increases in the effect of testosterone in certain tissues. The tissues showing the greatest sensitivity to testosterone may be the most important for mediating reproductive displays, but the identities of these tissues are largely unknown. I investigated this issue using the Bornean rock frog (Staurois parvus, family: Ranidae). This tropical anuran species deters sexual rivals through foot-flagging signals mediated by testosterone and ARs. I injected S. parvus males with testosterone plus flutamide, a drug that blocks all ARs, or testosterone plus bicalutamide, a drug that only blocks muscular ARs, and recorded the number of foot flags performed over time. My results indicate that both manipulations inhibit foot flagging, which suggests that ARs in the muscles are particularly important for performance of this behavior. Increased androgenic sensitivity in the muscles, rather than the central nervous system, thus likely evolved in parallel with this novel gestural signal. Overall, this study provides insight into how sexual selection acts on the tissues underlying reproductive displays to incorporate new behaviors into signaling repertoires






53 pages : illustrations (chiefly color) Includes bibliographical references (pages 29-33)