Meeting Abstract
The acute endocrine stress response plays an integral role in mediating trade-offs between current and future reproduction, suggesting that variation in acute stress responsiveness can be a critical determinant of fitness. How these principles unfold in the context of sexual selection is, however, poorly understood. Here, we build upon the “acute stress-fitness” framework in the context of intra- and intersexual selection in the green treefrog, Hyla cinerea. Males of this species produce vocalizations that stimulate production of the stress hormone corticosterone (CORT) in rival males, suggesting a central role for CORT in male-male competition. We predicted that acoustic stimulation of CORT production functions in an armament capacity by compromising rival male investment in courtship behavior and, hence, attractiveness. Consistent with this prediction, we show that CORT administration to calling males, simulating CORT production during vocal contests, rapidly decreases call duration and increases the probability of aggressive signaling and vocal abandonment – all of which reduce attractiveness to females. CORT-mediated effects were most prominent during simulated male interactions and occurred independently of changes in androgens, indicating that CORT effects are context-dependent and modulate androgen-dependent behaviors. Our results suggest that variation in acute stress responsiveness plays a pivotal role in intra- and intersexual selection and mediating the honesty of sexual signals.
