Intra-Specific Food Competition and Primate Social Structure: a Synthesis

Abstract

AbstractThe results of the various studies in this volume lead to a series of predictions about the relationships of group size to various components of food intake. Individuals in larger groups should generally encounter fewer new food sources per unit foraging effort than they would alone (prediction 1); an exception may occur when large groups defend areas of high food density against small groups. In addition, individuals in larger groups generally will suffer reduced intake per food source encountered because of increased sharing with other group members, at least for food sources that supply little total nutrient relative to an individual's satiation level for the nutrient (prediction 3) or are scarce relative to the spacing between individuals in the group (prediction 5). Individuals in larger groups may compensate for such reductions in foraging efficiency by increasing rates of food encounter (prediction 2), using food sources with greater amounts of nutrient (prediction 4), or increasing total foraging effort per day (prediction 6). Reduced foraging efficiency for a particular nutrient may not affect total intake of that nutrient if other nutrients require greater daily foraging effort (prediction 7). Food competition is expected to be highest in species using small and scarce food sources, subject to a high risk of predation, and with large satiation levels. An appendix on statistical problems describes some of the pitfalls inherent in studies of the kind presented in this volume.