PARENT SESSION
Contributed Oral Session 126: Mammal Ecology: Management, Reproduction, and Food Webs
Thursday, August 11, 8:00 AM - 11:30 AM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal

Feeding competition in long-tailed macaques (Macaca fascicularis): Can females by-pass the dominance order?

Dubuc, Constance^*,1, Chapais, Bernard¹, ¹ Université de Montréal, Montréal, Québec, Canada

ABSTRACT- Producer-scrounger models state that social foraging groups are composed of producers, who invest time and energy to find resources, and scroungers, who usurp discoveries from producers. Applied to despotic species, dominance rank should strongly influence tactical choices. Since being the first to reach a clumped feeding site is the only way to ensure a share, low-ranking individuals should be producers, while since excluding others carries no cost for high-ranking individuals, they should be scroungers. Some authors predicted that this game should exist in despotic primate species, whereas others rather expect arrival order to be positively correlated to dominance order in these species. Indeed, social retaliation can be postponed in primates and thus dominance order by-passing may be more costly than in birds. The aim of the present study is to provide an initial verification of the producer-scrounger game in macaques, the most studied of despotic primate species. Thus, we verified if low-ranking females could reach the feeding site before the highest-ranking individuals in order to increase their feeding gain in a captive group of long-tailed macaques. To evaluate various levels of competitive difference, we submitted the group to two experimental contexts (12 tests/context) differing in spatial distribution of a fixed amount of food (large vs. small patches); the competitive difference was higher in the small patch context. All intermediate- and low-ranking adult females (N=9) reached the site before the highest-ranking individuals at some point during the experiments, but the frequency could not be predicted by dominance rank. Females thus obtained significantly more food in both contexts, without experiencing more aggression. Interestingly, the tactic was significantly less used in the small-patch context and tended to be used more by low-ranking females having a preferential relationship with a dominant individual. Along with results obtained on a free-ranging group of capuchin monkeys, our results support the prediction that the producer-scrounger game may exists in despotic primate species. Nevertheless, strong social constraints may restrict the use to low risk contexts, either because of an intermediate competitive difference or of a higher tolerance from high-ranking individuals.

Key words: Primates, Feeding tactic, Dominance, Females