9407691 Marler ABSTRACT The goal of this research is to develop the mountain spiny lizard Sceloporus jarrovi as a model system for studying neuroendocrine control of territorial aggressive behavior. Aggressive behavior in this species is sterotypic, but there is both interseasonal and intraseasonal variation. Thus these lizards provide an ideal system for investigating how long term and short term gradations in aggression can be physiologically controlled while the animals are behaving in their natural environment. The focus for these studies will be the neuropeptide arginine vasotocin (AVT) which is known to influence reproductive behavior. A primary technique employed in the proposed research will be immunocytochemistry, which, through the use of image analysis techniques, will be used to compare concentrations of AVT within the brains of animals displaying varying levels of aggression. This technique will also allow identification of brain regions that may be associated with short and long term changes in aggression, as well as any morphological changes in AVT immunoreactive cells or fibers. Because of seasonal variation in the natural patterns of aggression and testosterone in S. jarrovi it will also be possible to uncouple the effects of testosterone and aggression on the expression of AVT-ir within the brain. Finally, the effects of artificially increased levels of AVT on territorial aggression will be examined while the animal is in its natural environment. These studies will begin to examine if AVT influences aggression in a strongly territorial species and how tightly coupled AVT is with testosterone and aggression.
