Patterns of lemur reproductive and behavioral development

Duke University, Durham NC

Investigators

Abstract

Traditionally, androgens have been linked with male development and estrogens with female development; yet, both classes of steroids are functionally significant in both sexes, with dramatic implications for sexual differentiation, reproductive development, and social behavior. In contrast to studies on the role of estrogens in males, the role of androgens in vertebrate females generally has been overlooked. A notable exception involves a series of studies examining androgen function in the female spotted hyena (Crocuta crocuta) - research that has challenged our assumptions of traditional sex roles and revealed a set of previously unknown mechanisms of hormonal regulation in females. Using the hyena as a predictive model, the specific aim here will be to address basic mechanisms of biobehavioral development in the ringtailed lemur (Lemur catta), an endangered prosimian primate endemic to Madagascar. The selection of L. catta as the subject of this proposal is based on the existence of a set of male-like characteristics in the female, including exaggerated or 'masculinized' external genitalia, size monomorphism with the male, and aggressively mediated social dominance over males. The proposed research will compare females against males to (1) fully characterize the suite of male-like traits in the female, (2) examine the hormonal correlates and developmental processes of those traits, and (3) explore the social factors influencing the behavioral expression of sex differences, particularly during aggression, play, and scent marking. As a nontraditional animal model, the ringtailed lemur presents an invaluable opportunity to examine current theories of sexual differentiation, to explore the role of androgens in mediating female aggressive behavior, and to elucidate the biological mechanism associated with the evolution of a female-driven social system in primates. The results of this research are likely to raise provocative questions about the traditional focus on male-driven mechanisms at the expense of considering female social and reproductive control. The findings may also suggest a broader role for androgens in female mammals and may ultimately contribute to reformulating the theory of sexual differentiation to better reflect active processes in feminine development. The broader impact of this project will be attained primarily through a strong commitment to undergraduate and graduate training. Through hands-on research participation that fosters new collaborations and interdepartmental partnerships, this project will provide a venue for encouraging under-represented groups, particularly women, to pursue careers in science. By sharing information with the Duke University Primate Center's on-site educational program, that targets universities, primary schools, and the general public, this project will contribute to the mission of enhancing education and raising public awareness about lemurs. Moreover, any knowledge gained on lemur reproduction could ultimately benefit species conservation efforts.