Meeting Abstract

P1.43  Wednesday, Jan. 4  Decreased Aggression without Loss of Territory Following Cortisol Injection in Male Cichlids. MOVIUS, Morgan A.*; AUBIN-HORTH, Nadia; RENN, Suzy CP; Reed College; Laval University; Reed College

In group-living species, an individual’s dominance rank in the social group influences all crucial aspects of its life, including reproduction and survival. The social environment dramatically impacts the expression of complex behaviors. Males of the African cichlid species Astatotilapi burtioni, have served as a model system to study the neural, endocrine, and molecular basis of socially plastic phenotypes that encompass male dominance, reproduction capacity and growth. Multiple lines of research suggest that increased expression of the neuropeptide AVT is correlated with social dominance, however recent pharmacological experiments revealed an increased probability of territory loss following injections with AVT. In order to test the possibility that this effect was mediated through activation of the stress response we increased systemic cortisol levels in dominant males with repeated injections. We found that while cortisol injections caused a significant decrease in aggressive behavior, it did not cause social descent from the dominant to subordinate phenotype. This result suggests that while cortisol plays a role in the behavioral regulation of aggression, it is not sufficient to determine the phenotype of cichlid males