Meeting Abstract
Understanding the social behavior of animals involves the integration of ultimate and proximate explanations. Evolutionarily, the social choices made by individuals are vital to their survival and reproduction. The ultimate evolutionary explanations of social behavior have been well-supported by numerous empirical studies: one or more of the animals involved in the social interaction experiences some benefit. Determining the proximate mechanisms of affiliative behaviors are a bit more complex. Cortisol expression has been suggested, as social contact, or the lack thereof, is often associated with the stress response. Interestingly, studies have also indicated significant sex differences in measured cortisol levels. Our goal is to utilize zebrafish (Danio rerio ) to determine if the expression of social behavior is related to differences in cortisol levels. We have found that while both sexes readily shoal with groups of zebrafish rather than spend time alone, significant sex differences are apparent when examining specific aspects of shoaling choices, related to shoal size and body coloration. We are currently using a water-borne hormone extraction protocol and EIA to determine how these real-time shoal choice behaviors, and the observed sex differences, correlate with endogenous cortisol expression.
