9722823 Schoech The primary goal of this project is to determine the hormonal mechanisms that mediate parental and alloparental behavior in a social species, the Florida scrub-jay (Aphelocoma coerulescens). Because prolactin is associated with parental behavior in many species, including Florida scrub-jays, the thrust of the project will address the role of prolactin in promoting helping behavior by nonbreeders. Previous correlative studies have linked helping and prolactin in this species. This proposal uses a protocol whereby manipulations of hormone levels allow more definitive assessment of hormone function. It has long been known that until a hormone is removed and replaced experimentally, the causal nature of the compound can only be inferred. Recent advances in our understanding of the compounds 'upstream' from the pituitary that control the secretion of prolactin make it possible to remove prolactin with biological elements. Using a prolactin releasing agent, and by treating Florida scrub-jays with anti-bodies against this agent, prolactin can be immunoneutralized. Following removal of the hormone of interest (prolactin), focal observations of treated individuals will allow the determination of whether prolactin is responsible for helping behavior. Similarly, modern field endocrine techniques allow enhancement of an organism's endogenous hormone titres. By removing and then supplementing prolactin in free-living cooperatively breeding Florida scrub-jays, this proposal will pioneer the use of these valuable techniques under field conditions. In addition to greatly enhancing our understanding of hormonal mechanisms that mediate social behavior, the methods used in this proposal may prove to be useful in manipulating behavior, and may set the stage for future research in a variety of species.
