Drivers and consequences of variation in individual social connectivity

There is a growing interest in identifying specific causes and consequences of variation in individual social behaviour as a means of understanding how different individuals balance the costs and benefits of group living. In this study, we used social networks to examine variation in individual social behaviour in wild Grant's gazelles, Nanger granti, and explored potential drivers and consequences of this variation. First, we quantified two aspects of individual network position (weighted degree and closeness) on a monthly basis for 12 consecutive months and examined life-history (age) and abiotic (rainfall) factors that could explain among-individual variation in network position. Next, we examined the level of within-individual repeatability in network position over time. We then tested for potential consequences of this variation focusing on parasite infection and diet quality. Rainfall and age were strong predictors of variation in closeness but not degree. Interestingly, we found that one aspect of individual network position (closeness) varied over time, while another (degree) was moderately repeatable. The difference in within-individual repeatability of the two measures may be explained by the dependence of closeness on rainfall. In addition, we found that individual network position had consequences for both parasitism and diet, but the magnitude and direction of these effects depended on parasite type, connectivity measure and environmental conditions. Overall, our results suggest that environmental and host factors strongly influence variability in certain aspects of social connectivity in Grant's gazelles, and that abiotic and biotic forces, together, mediate the consequences of social network position.