Subgrouping Patterns in a Group of Wild Emphasis

Authors: Jessica W Lynch Alfaro

Publish Date: 2007/05/24

Volume: 28, Issue: 2, Pages: 271-289

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Abstract

Seasonal patterns of group fragmentation including the size of subgroups and percentage of time spent in subgroups may provide information on individual decisionmaking in response to resource distribution Agesex class composition of subgroup membership can offer insights into the social dynamics of the group as a whole At most field sites capuchins Cebus spp form stable groups with no evidence of group fragmentation Here I describe seasonal subgrouping patterns including proportion of time spent in subgroups subgroup size agesex membership dyadic fidelity stability of membership and the effect of subgrouping on individual foraging efficiency in a group of wild Cebus apella nigritus From September 1996 to August 1997 the study group at the Estação Biológica de Caratinga Brazil divided into 148 different subgroups on 99 of 194 census days In contrast to expectations for subgrouping patterns as a response to seasonal distribution of resources the proportion of days spent in subgroups did not vary significantly by season Subgroup composition was relatively fluid with multimale multifemale subgroups the most common throughout the year Unimale multifemale subgroups were restricted to the wet season in contrast allmale subgroups and unimale unifemale subgroups occurred in the dry season For both males and females low rank predicted membership in smaller subgroups For males but not females subgrouping coincided with increased foraging efficiency as measured by increased time spent ingesting food and decreased time spent traveling on days with subgrouping compared to days with the group in a cohesive unitI thank Karen B Strier University of WisconsinMadison José Rímoli Universidade Católica Dom Bosco David Morales Torres Universidad Veracruzana Sérgio Lucena Mendes Museo de Biologia Mello Leitão and Michael Edward Alfaro Washington State University Alice Guimarães Andreia Silene Oliva Laiena Texeira Dib Rogério Ribeiro dos Santos Jairo Gomes Eduardo Veado and the EBC staff made work at Caratinga a pleasure This research was supported by grants from Fulbright/IIE WennerGren Foundation Predoctoral Grant 6068 Tinker Foundation/Nave Fund and a National Science Foundation Graduate Fellowship

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