Abstract # 3034 Event # 200:

Scheduled for Monday, September 19, 2011 08:15 AM-08:30 AM: Session 25 (Meeting Room 408) Oral Presentation


PRESENCE OF ESTROUS FEMALES ASSOCIATED WITH REDUCED FEEDING TIME IN MALE CHIMPANZEES AT KANYAWARA (UGANDA) REGARDLESS OF THEIR DOMINANCE RANK

A. V. Georgiev1, A. F. Russell2, M. Emery Thompson3, M. N. Muller3 and R. W. Wrangham1
1Harvard University, Department of Human Evolutionary Biology, Peabody Museum, 11 Divinity Ave, Cambridge, MA 02138, USA, 2Centre for Ecology & Conservation, University of Exeter, UK, 3Department of Anthropology, University of New Mexico
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The energetic costs of competing for mates may place critical constraints on both male dominance rank and reproductive success in promiscuous primates. We tested whether the presence of estrous females compromises foraging among male chimpanzees (Pan troglodytes), a species with moderate reproductive skew and non-seasonal breeding. We conducted full-day focal observations on 12 adult males (N = 85 days) in Kibale National Park, Uganda, in the presence and absence of estrous females. Using linear mixed models, we found that in the presence of estrous females, all males spent less time feeding (from a mean % ± SE of 44.1 ± 1.4 to 35.3±1.8: F(1,78)=14.10, p<0.001), irrespective of rank (F(2,76) = 0.69; p = 0.5). This effect was found after controlling for variation in party size and fruit availability. There was no evidence that males offset lost feeding time by increasing the time feeding on ripe fruit (F(1,77)=0.98, p=0.32). These observations suggest that male caloric intake is negatively impacted by mating activity but do not indicate that the costs are higher for high-ranking males, who engage in mating activity the most. Additional components, such as the energy expended during competition and overall energy balance are expected to contribute to rank differences in the costs of reproduction.