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 effect of
health status on social behavior in a non-human primate.