Meeting Abstract
During the lifetime of an organism, key events are orchestrated by a confluence of environmental, social, and physiological factors to promote reproductive success. In the bi-directionally sex changing fish, Lythrypnus dalli, stable haremic groups maintain a linear social hierarchy. Status instability follows immediately after male removal, causing transiently elevated agonistic interactions and increase in brain and systemic levels of a potent fish androgen, 11-ketotestosterone (KT). Coupling KT implants with a socially inhibitory environment for protogynous sex change induces rapid transition to male morphology, but no significant change in social behavior and status occurs. Here, we examined whether coupling a social environment permissive to sex change would influence KT effects on agonistic behavior. We implanted cholesterol (control) or KT in the dominant individual (alpha) undergoing sex change (on d0) and determined the effects on behavior and the degree to which administered steroids altered the steroid load within tissues. During the period of social instability, there were rapid (within 2 h), but transient effects of KT on agonistic behavior in alphas, and secondary effects on betas. On d3 and d5, all KT, but no cholesterol-treated females had male typical genital papillae. Despite elevated brain and systemic KT 5 d after implant, overall rates of aggressive behavior remained unaffected providing no evidence for the notion that hormones drive behavior with an “on-off” switch mechanism. These data highlight the importance of social context in mediating complex hormone-behavior relationships.
