Sex differences in reconciliation and post-conflict anxiety in bonnet macaques

Rates of reconciliation vary widely between different types of opponents, and post-conflict anxiety has been proposed to mediate individual variation in reconciliation rates. We investigated the form and function of reconciliation in a wild, provisioned group of bonnet macaques (Macaca radiata) with the prediction that sex differences in post-conflict anxiety would be associated with sex differences in conciliatory tendency. Individuals in the study group had a conciliatory tendency of 29.3%. Victims avoided their former opponents at a higher rate following aggression than during matched-control samples, and reconciliation decreased the rate of avoidance. Although victims showed a higher rate of anxiety-related behavior than did aggressors, anxiety-related behavior was elevated after aggression and reduced following reconciliation in both victims and aggressors. Female-female opponents showed higher rates of anxiety-related behavior before reconciliation than they did following unreconciled aggression. In contrast, male-male and female-male opponents showed increased anxiety-related behavior following aggression regardless of the occurrence of reconciliation. Moreover, female-female opponents had a higher conciliatory tendency than did female-male opponents. The elevated post-conflict anxiety shown by female-female opponents before reconciliation, along with their high conciliatory tendency, suggests that post-conflict anxiety promotes reconciliation. In sum, the sex differences in post-conflict behavior found in this study support the hypothesis that variation in post-conflict anxiety mediates differential rates of reconciliation.