Abstract # 13224 Event # 127:

Scheduled for Friday, August 10, 2018 10:30 AM-10:45 AM: (Chula Vista ) Oral Presentation


VARIATION IN FORAGING AND FRUIT SELECTION ACROSS AGE AND SEX CLASSES OF WHITE-FACED CAPUCHIN MONKEYS (CEBUS CAPUCINUS IMITATOR)

R. E. Williamson1, S. E. Webb1, L. M. Fedigan1 and A. D. Melin1,2
1University of Calgary, Department of Anthropology and Archaeology, Calgary, AB T2N 1N4, USA, 2Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1
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     Individual differences in shared habitat use and food selection—or niche divergence—may minimize within-group competition. Previous studies of primates have focused on examining such differences across sex classes, and we expanded upon this by investigating whether niche divergence occurs across both age and sex classes of wild white-faced capuchins. We hypothesized that juveniles and females would select easy-to-process fruits more often than adults and males, respectively. Data were collected from four groups of capuchins (n=113) in Costa Rica from April – September 2016 and January – July 2017. Groups were followed dawn-to-dusk, and individual instantaneous scans were recorded at 30-minute intervals. We analyzed a subset of 601 fruit foraging scans of 5 different taxa. We categorized fruits based on processing difficulty, as measured by an FLS-1 mechanical tester and calculated chi-square tests of independence (p<0.05) to compare the frequencies of foraging on “easy” and “difficult” fruit species between age classes and sex classes. There were no significant differences between age classes for foraging frequencies on easy or difficult fruits. However, the foraging frequencies between one easy/difficult fruit pair were found to be significantly different (chi²(1)=7.7997, p=0.005226) between the sexes. Males foraged on the easy species more often than females. These results contradict our original hypotheses. They indicate that in the fruit species analyzed, niche divergence in food selection occurs between sex but not age classes.