Abstract # 4213 Event # 115:

Scheduled for Friday, June 22, 2012 02:15 PM-02:30 PM: Session 18 (Camellia ) Oral Presentation


GROUP SIZE AND SUBSTRATE USE, NOT FOOD TYPE, PREDICT RATES OF AGONISM AMONG FEMALE PRIMATES

A. Koenig1, C. J. Scarry2 and B. C. Wheeler3
1Stony Brook University, Department of Anthropology, Stony Brook, NY 11794-4364, USA, 2Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, NY 11794-4364, USA, 3Cognitive Ethology Laboratory, German Primate Center, 37077 Goettingen, Germany
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     The ecological model of female social relationships predicts an association of clumped, depletable patches with high rates of agonism over food. Fruits are frequently assumed to represent such contestable resources. Here, we test this assumption and also include female group size and substrate use (terrestrial, arboreal) as predictors of agonism. We searched the literature for data on adult female-female agonistic behavior in group-living primates (excluding pair-living species). Data were derived exclusively from focal animal sampling and included 49 wild, unprovisioned groups from 25 primate taxa (4 Strepsirrhini, 4 Platyrrhini, 5 Colobinae, 10 Cercopithecinae, 2 Hominoidea). For the analysis we used least squares regressions (LS), ANOVAs, and phylogenetic generalized least squares regressions (PGLS). We found no effect of diet on rates of agonism (for fruits, leaves, or animal matter: LS p>0.1; PGLS p>0.1). In contrast, rates of agonism increased significantly with female group size (LS p<0.001; PGLS p<0.001). Additionally, terrestrial taxa showed significantly more agonism (ANOVA p<0.001; PGLS p<0.01). In a combined test of one diet variable with female group size and substrate use, either female group size and substrate use (LS p<0.05) or only female group size were significant (PGLS p<0.05). These findings contradict the common assumption that food type mediates interference competition. Rather, the frequency of agonism seems to be driven by the density of competitors and possibly the risks associated with fighting.