Studies of hormone-behavior interactions have attempted to answer two central questions: How do social conditions modify individual hormone patterns? How do hormones modulate behavior? Dr Phillips and his colleague Dr. Lance propose to investigate the interrelationship between a male's social dominance and its circulating hormone levels and social environment. This interplay between hormone levels and social conditions is most apparent in adult populations during the breeding season. Yet, recent studies suggest that many behavior patterns were established when the individual was a juvenile. Dr. Phillips has developed an excellent model system to determine to what extent a male's social dominance is shaped during development by both its physiology and social environment. He will study a population of green iguanas from hatching to puberty. This species is perhaps the only reptile where such a developmental study of social structure and corresponding hormone levels is feasible. Indeed given that reptiles are a pivotal group in vertebrate evolution, the studies will also provide insight into how the interactions among hormones and behavior may have evolved.
