Paternal Relatedness Predicts the Strength of Social Bonds among Female Rhesus Macaques

Abstract

Forming strong, equitable, and enduring social bonds with a few individuals in a group carries adaptive benefits in terms of increased longevity, offspring survival and paternity success in birds and mammals, including humans. These recent insights generated a new interest in the factors creating variation in the strength of social relationships. Whether and how animals discriminate paternal kin from non-kin and bias their social behavior accordingly is being debated. This study explores the relative importance of dominance rank, age, maternal and paternal relatedness in shaping dyadic affiliative relationships in a group of 30 captive rhesus macaque females. The strength of social relationships, measured by the composite sociality index from observational data, was independently predicted in GLMMs by both maternal and paternal relatedness as well as rank similarity. In addition, social bonds between paternal half-sisters were stronger than between distantly related kin suggesting that females biased their affiliative effort towards paternal relatives. Despite identical relatedness coefficients bonds between mothers and their daughters were three times as strong as those between full sisters. Together these results add to the growing body of evidence for paternal kin biases in affiliative behavior and highlight that females prefer descendent over lateral kin.

The neuroethology of friendship

“…In these primates, kin-biased affiliative interactions, often measured using grooming and proximity, are common. 36 These include interactions between close maternal relatives (mother-daughters, maternal-siblings) [37][38][39][40][41][42] and, to a lesser extent, paternal relatives [38][39][40][41] (Fig. 2).…”

Maternal kin bias in affiliative behavior among wild adult female blue monkeys

“…Recent studies have also documented kin bias among paternally related cercopithecine females. Adult female baboons showed similar affiliative bias toward maternal and paternal half-sisters [Smith et al, 2003], whereas female rhesus macaques showed a stronger affiliative kin bias to maternal than to paternal half-sisters [Schülke et al, 2013;Widdig et al, 2001Widdig et al, , 2006. The strength of affiliation of paternal relatives may depend on whether there are strong bonds with maternal kin [Charpentier et al, 2012;Silk et al, 2006].…”

“…In almost all cercopithecines, females are philopatric and live together with their female kin for life. Close maternal kin commonly show high levels of affiliation [reviewed in Berman, 2011; more recent reports by Charpentier et al, 2012;Schülke et al, 2013;Johnson et al, 2014]. Recent studies have also documented kin bias among paternally related cercopithecine females.…”

The consequences of unidentifiable individuals for the analysis of an animal social network

“…Recent studies have linked social position to home range (see Pinter-Wollman et al, 2013 for a review), social status (Sueur & Petit, 2008), age (Patriquin, Leonard, Broders, & Garroway, 2010), sex (Carter Seddon, Fr ere, Carter, & Goldizen 2013;Gilby & Wrangham, 2008), genetic relatedness (Archie, Moss, & Alberts, 2006;Carter, Seddon, Fr ere, Carter, & Goldizen, 2013;Schülke, Wenzel, & Ostner, 2013), the acquisition of social information (Aplin, Farine, Morand-Ferron, & Sheldon, 2012;Aplin et al, 2014;Claidiere, Messer, Hoppitt, & Whiten, 2013), disease status (Weber et al, 2013) and reproductive success (Wey et al, 2013). Additionally, there has been increasing recent interest in social network position as a personality trait or part of a wider behavioural syndrome (Krause, James, & Croft, 2010;Wilson, Krause, Dingemanse, & Krause, 2013).…”