Abstract # 2070 Event # 235:

Scheduled for Saturday, August 19, 2006 01:15 PM-01:30 PM: Session 23 (Regency East #2) Oral Presentation

A Comparison of the Diets of Male and Female Phayre’s Leaf Monkeys (Trachypithecus phayrei) at the Phu Khieo Wildlife Sanctuary, Thailand.

S. A. Suarez
Miami University, Anthropology Department, Upham Hall 164, Oxford, OH 45056, USA
     Due to differences in nutritional requirements, basal metabolic rates resulting from body-size dimorphism, and dissimilar activity budgets due to differences in social obligations, male and female primates should show differences in food choice. Phayre’s leaf monkeys are predicted to show sexual differences in diet because they are body-size dimorphic, and because infants are dependant for about one year. I therefore compared the feeding behavior of four adult males and nineteen adult females from three social groups of wild Phayre’s leaf monkeys in the Phu Khieo Wildlife Sanctuary, Thailand. I conducted instantaneous samples of behavior at one-minute intervals during five 20-minute data collection protocols of each focal subject per month, from April 2004 to May 2005 (n = 27,160). I described food items, marked feeding patches, and sampled ingestion rates when focal subjects fed. Nonparametric tests revealed no differences between males and females in feeding time consuming fruits, leaves, or flowers. Males and females also did not differ in preference for particular plant species. Males and females did differ in ingestion rate for most fruit species. Males consumed young seeds of the key species Afzelia xylocarpa more rapidly than did females, as stronger muscles and larger canines facilitated processing of the fruit’s hard exocarp. Dimorphism in Phayre’s leaf monkeys may allow males greater access to seasonally important, hard-to-access high-quality foods. Project funded by National Science Foundation (BSC-0215542).