Producers and scroungers in tufted capuchin monkeys, Cebus apella nigritus

DI BITETTI, M. S.; JANSON, C. H.

Zurich

Congreso; 8° International Behavioral Ecology Congress; 2000

Group living can confer advantages to individuals, but it can also impose severe costs through resource competition. Some individuals in a social group may primarily discover food while others scrounge on these newly discovered resources. This type of social foraging has been modeled as a producing-scrounging game. We describe how the spatial location and the rank of individuals in a group of wild tufted capuchin monkeys affect their ability to discover and exploit new food sources. By placing platforms filled with bananas at novel locations in their home range, we show that animals in the leading edge of a foraging group have a higher probability of discovering new food sources than animals occupying other spatial positions. Animals that discover more food patches also consume more on average. The fraction of food in a patch consumed by the finder was negatively related to the amount of food in the resource and positively to its dominance rank and the time elapsed until the arrival of other individuals to the resource. However, the alpha male and the alpha female, which tended to occupy central-forward positions, were able to monopolize newly discovered food sources and thus obtain a major share of them. In capuchin monkeys, scrounging occurs in slowly renewing or non-renewing resources, which occur at low to moderate densities, and when the handling time of the resource is moderate to large. These conditions occur naturally at the start of the lean season when they mostly exploit palm fruits.