Hormonal mechanisms of mate choice

Abstract

SYNOPSIS. Mate choice is a critically important determinant of reproductive success. Because of its significance in the evolutionary process, it has received a great deal of attention from animal behaviorists interested in ultimate causes of behavior. Much less effort has been directed at uncovering the physiological mechanisms of mate choice, including those operating during ontogeny that lead to adult mate preferences. As a result of natural and sexual selection, many aspects of mate choice are sexually dimorphic. How do adult males and females of the same species come to show different mating partner preferences? One possibility is that sex steroid hormones play important roles, acting either during early development to permanently establish sex differences or during adulthood to facilitate their expression, roles similar to the organizational and activational effects of sex steroids on sexually dimorphic copulatory and courtship behavior patterns. This review (1) summarizes what is known about hormones and mate choice, highlighting those ' results most relevant to understanding proximate causation from an evolutionary perspective; (2) describes recent work from the author's lab testing an organizational hormone hypothesis of mate choice, focusing on a particularly widespread and robust aspect of mate choice-preference for opposite sex partners-in a pair bonding species-the zebra finch; and (3) suggests some future directions for research that might integrate ultimate and proximate causation.