Smithsonian Tropical Research Institute, Smithsonian Institution, School of Human Evolution & Social Change, Arizona State University
Friday 4:45-5:00, Ballroom C
Sex differences in primate feeding ecology are a common phenomenon, but for most species it is unknown when in development they appear and how they are related to metabolic and ecological strategies of males and females. They may function to minimize feeding competition within a group or may simply be a behavioral response that compensate for fluctuating physiological costs, particularly to females during reproduction. Clutton-Brock (1977) proposed three potential scenarios for the evolution of sex differences in feeding ecology: (1) sexual size dimorphism, (2) costs of reproduction, and (3) ecological competition avoidance or niche partitioning. As a primate-wide pattern, sexual size dimorphism does not reliably predict sex differences in feeding, emphasizing a need for a better understanding of how female reproductive costs and niche partitioning structure ecological sex differences. Using a mixed-longitudinal sample of ring-tailed lemurs (Lemur catta) at the Beza Mahafaly Special Reserve we show that both reproductive costs and niche partitioning structure sex differences in the feeding ecology of ring-tailed lemurs. Sex differences in this species are strongest when females are lactating, but there is early divergence of dietary diversity between males and females that begins at weaning and continues through adulthood. The early emergence of sex differences in dietary diversity in juvenility that are maintained throughout adulthood indicate that niche partitioning is an important and overlooked aspect of sex differential feeding ecology, and that ontogenetic studies of feeding are particularly valuable to understanding how selection shapes adult, species-typical diets.
This work was funded in part by a National Science Foundation DDIG (BCS 0851761), the J. William Fulbright Foundation, Primate Conservation, Inc,, Sigma Xi and its ASU chapter, the ASU Graduate and Professional Students Association, and the ASU School of Human Evolution & Social Change.