Unconditional care from close maternal kin in the face of parasites

Several species mitigate relationships according to their conspecifics’ parasite status. Yet, such strategy of defense comes with costs of depriving individuals from valuable social bonds. Animals therefore face a trade-off between costs of pathogen exposure and benefits of social relationships. According to models of social evolution, social bonds are highly kin-biased. However, whether kinship mitigates social avoidance of contagious individuals has never been tested so far. Here, we build on previous research to demonstrate that mandrills (Mandrillus sphinx) modulate social avoidance of contagious individuals according to kinship: individuals do not avoid grooming their close maternal kin when contagious (parasitized with oro-fecally transmitted protozoa), although they do for more distant or non-kin. While individuals’ parasite status has seldom been considered as a trait impacting social relationships in animals, this study goes a step beyond by showing that kinship balances the ef...