Abstract # 3141 Event # 238:

Scheduled for Monday, September 19, 2011 02:45 PM-03:00 PM: Session 34 (Salon F (Sixth Floor)) Oral Presentation


THE ROLE OF NUTRITIONAL AND MECHANICAL PROPERTIES IN FEEDING SELECTIVITY OF JUVENILE PHAYRE'S LEAF MONKEYS (TRACHYPITHECUS PHAYREI CREPUSCULUS)

K. Ossi-Lupo1 and A. Koenig2
1Stony Brook University, Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook, NY 11794, USA, 2Department of Anthropology, Stony Brook University
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Juvenile primates are known to often differ from adults in diet composition and/or feeding times, but the role that food properties might play in driving these differences is less clear. This study investigated potential predictors (i.e., nutritional content and food toughness) of feeding time for 25 Phayre’s leaf monkeys (Trachypithecus phayrei crepusculus) at Phu Khieo Wildlife Sanctuary, Thailand. Feeding data were collected for four months via focal sampling (280 hours) using one-minute instantaneous recording for adults (N=12), older juveniles (N=7), and younger juveniles (N=6). Food toughness was measured with a portable mechanical tester and nutritional content assessed from dried samples. Nutritional and toughness data were available for an average of 75.6% of individuals' diets (range: 41.9 - 93.7%). Gross energy was a significant negative predictor (cal/g; p<0.01) and protein-to-fiber ratio a significant positive predictor (p=0.02) of time spent feeding. As expected, feeding times differed across age classes (p<0.01). While gross energy negatively affected adult feeding time (p=0.02), protein-to-fiber ratio (p<0.01) was the best (positive) predictor for older juveniles. By testing foods separately, we found toughness negatively affected leaf-eating for adults (p<0.01) and fruit- and seed-eating for younger juveniles (p=0.03). While nutritional components seem to be the primary influence on overall food selection, food properties affect age classes differently. Supported by ASP, Leakey Foundation, NSF DDIG (BCS-0647837), NSF (BCS-0542035), Wenner-Gren Foundation and Stony Brook University.