MOORE, Paul A.; BERGMAN, Daniel; Bowling Green State University, Bowling Green, OH 43403; Bowling Green State University, Bowling Green, OH 43403: The role of intrinsic and extrinsic factors in determining social status in crayfish

Individuals commonly modify their behavior in the presence of a conspecific. This is particularly true in the context of aggressive exchanges, where group members form a web of social relationships in species ranging from anemones to humans. Although hierarchical structures are a widespread phenomenon, the dynamic processes which produce them remain poorly understood. In particular, it is the exchange of information during agonistic interactions that give rise or can alter the outcomes of those interactions. Given the theoretical appeal of these interactions, the evolutionary importance, and the broad taxonomic spread, it is not surprising that the sensory mechanisms involved in the formation and maintenance of hierarchical structures have received some recent attention. In crayfish, dominance was thought to be largely determined by physical superiority, encounters are purely dyadic without incidences of coalitions, fighting behavior is highly stereotyped, and the outcome of encounters can be judged reliably. Recent evidence has shown that dyadic encounters are dependent upon a number of other factors including the exchange of chemical information during encounters, previous history, and the internal neurochemical state. We propose to provide a comprehensive analysis of the extrinsic processes (previous history, sensory communication, etc.) and intrinsic processes (neurochemical state) that produce and maintain dyadic dominance relations and social hierarchies in crayfish. We hope that this review will bring together a global picture of all of the processes that determine an organisms social standing.