“The coevolution of parasite and host has not only influenced the evolution of defense mechanisms but also the evolution of social systems,”
This research suggests that parasites, similarly to kinship ties and social rank, influence mandrill behavior by shaping social dynamics in their group. This study of the evolution of antiparasitic behavior is currently focused on the influence of parasites spread merely by contact. But it could expand its scope to include other mandrill pathogens with different routes of transmission, such as nematodes spread through contact with the environment or retroviruses spread from male to male by biting.
Humans — like most non-human primates — are social beings and profit in many respects from the benefits of a community. However, their closeness to conspecifics is an opportunity for pathogens and parasites to infect new hosts. It is therefore advantageous to avoid sick individuals. Scientists including Clémence Poirotte from the German Primate Center investigated how mandrills, an Old World monkey species inhabiting equatorial rainforests of Gabon, recognize conspecifics infected with intestinal parasites and avoid an infection. The monkeys are able to smell an infected group member and consequently groom them less than healthy individuals. This component of the “behavioral immune system” of mandrills plays a crucial role in the co-evolution of host and parasite.