9709159 Riechert It is well known that behavior is influenced not only by the design of an animal's nervous system, but also by chemicals produced by its endocrine system (i.e., hormones). These two influences interact in determining individual behavior and both systems are genetically determined. This study tests the validity of the Conflicting Tendency Model, proposed to explain the potential interaction between factors that operate antagonistically in determining the behavior of individuals on a continuum from 'fearful' to 'aggressive.' The PI has identified a possible genetic basis for territorial behavior in a well-studied animal model system (the desert funnel-web spider Agelenopsis aperta), in which the action of each of two antagonistic factors - one controlling tendency to flee or 'fear', and the other determining tendency to attack or 'aggression' - can be separated through selected breeding experiments. By comparison of the behavior of spiders from populations that differ in tendency to escalate fights, respond to predators and attack prey, and selectively bred genetic lineages, the PI will examine genetically-based aggressive tendency. In addition to testing the hypothesis that hormones may act in opposition to one another in determining motivational states, the work is important for the insight it provides into the genetic bases of such complex behavioral traits as fighting behavior, boldness towards predators, and attack responses towards prey.
