Kinship, Ectoparasites, and Reproductive Success in Cape Ground Squirrel (Xerus Inauris) Social Networks PDF Download

Author: Philip Shimel
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Languages : en
Pages : 0

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Book Description
Sociality - or living in groups among members of the same species - can have both costs and benefits for survival and reproductive success. Inclusive fitness theory suggests organisms might behaviourally favour closer kin if they can identify and act to benefit them. In promiscuous social species, average relatedness may be too low to maintain costly social behaviours like cooperative breeding without kin discrimination. Animals that are more central in social networks may gain fitness benefits and costs similar to those of sociality generally, but particularly those effects that arise from indirect social connections. Increased social network centrality is often linked to improved fitness, but also greater ectoparasite abundance. Exploring whether fitness correlates to social network position under low rates of aggression or hierarchy remains a key challenge for comparative evolutionary ecology. Cape ground squirrels (Xerus inauris) are facultatively cooperative breeders with high promiscuity. They are a social species that rarely exhibit aggressive behaviours towards conspecifics and show no evidence of dominance hierarchies. A previous study that removed their parasites dramatically increased female reproductive success. Our objective was to examine whether kinship influences social structure and whether ectoparasite abundance and centrality influence survival and reproductive success in adult female Cape ground squirrels. We predicted kinship increases affiliative and decreases agonistic interactions, that centrality increases ectoparasites, and that ectoparasites and centrality reduce reproductive success but not survival. We studied Cape ground squirrels on S.A. Lombard Nature Reserve, South Africa in 2017. We followed 14 social groups, collected interaction data through all-occurrence sampling, and collected ectoparasite abundance data from trapping. We found that kinship increased both affiliative and agonistic interactions. Since agonistic interactions are relatively mild in this species, greater agonistic interaction frequencies with closer kin may have insignificant fitness costs. More central adult females had more ectoparasites, but eigenvector centrality and ectoparasite abundance did not affect survival or reproductive success. Our study shows that Cape ground squirrels are nepotistic with their interactions within their social groups, and that the costs and benefits of group living in species with low rates of aggression can have novel implications for the relationships between fitness and sociality.