Parallel dispersal and its effec on the kin composition of groups in a gregarious primate (Cebus capucinus)

 Despite a growing number of studies reporting parallel dispersal, it is not clear how this dispersal pattern a.ects the distribution of kin or the occurrence of kin cooperation in the dispersed sex. To further our understanding of the temporal and spatial distribution of kin in a population with male parallel dispersal, we collected demographic and genetic data from white-faced capuchins (Cebus capucinus) at Santa Rosa National Park, Costa Rica, between 2007 and 2013. Based on the demographic database, we classified animals as natal, single immigrant, or parallel immigrant (i.e. transferred between groups with familiar kin or non-kin). We genotyped all adult and subadult animals in 5 study groups at 15 short tandem repeat loci, and we calculated their estimated relatedness values. As predicted in a population with female philopatry and male dispersal, females but not males were more closely related within than between groups. However, females were not always more closely related than males residing in the same group due to influxes of parallel immigrant male kin. Within bisexual social groups, parallel immigrant males resided with a similar number of same-sexed kin as natal females did. Thus, males have opportunities to develop cooperative kin relationships in species such as the white-faced capuchins in which parallel dispersal is common. Because parallel dispersal can have important consequences for the evolution of kin cooperation, this dispersal pattern should be taken into account in future models of the evolution of social structure.