Social integration in temporal multiplex association networks predicts offspring survival in female geoffroy’s spider monkeys (Ateles geoffroyi)

Abstract

While sociality is considered an important factor influencing female reproductive success, it is unclear how temporal social dynamics relate to it. We address this by evaluating the influence of social integration and its stability over time on offspring production and survival in Geoffroy’s spider monkeys ( Ateles geoffroyi ). Using 52,670 subgroup scan samples collected every 20 min for a mean (± SD) of 15 ± 7 scans per day over 24 years from 31 January 1997 to 10 December 2020 (with a mean of 2,195 ± 892 scan samples per year), we compiled yearly association matrices among the sexually mature individuals of a wild group of spider monkeys, based on co-occurrence of two individuals in the same subgroup. We built Bayesian edge-weight models with the association matrices and generated 1000 samples of each yearly network, which we then used as layers in temporal multiplex networks. For each female with adult tenure ≥ 5 years ( n = 17), we estimated strength and eigenvector versatility in the multiplex network that comprised the last 5 years of her tenure. We also estimated six (monolayer) centrality-based metrics in the yearly networks of females with adult-tenure ≥ 1 year and at least one recorded offspring born in the group ( n = 22). We tested the influence of these eight indicators of social integration as predictors of offspring production and survival. Results showed overall positive relationships between social integration and offspring survival, but not offspring production. The former could be due to better access to food resources or protection from within-group aggression. Our temporal multilayer approach contributed to the body of evidence regarding the fitness benefits of sociality.

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