Faecal avoidance differs between the sexes but not with nematode infection risk in mandrills

Abstract

Animals have evolved a wide range of behaviours that act as barriers to decrease the risk of parasite infection. Faecal avoidance may, for example, limit contact with orofaecally transmitted parasites, such as gastrointestinal nematodes. When present in faeces, however, nematode eggs need to mature before reaching their infective stage. If strategies have evolved in hosts to specifically avoid nematodes, old faeces with infective larvae should elicit stronger avoidance behaviour than fresh faeces that contain noninfective stages. Here, we carried out two experiments to test the hypothesis that mandrills, Mandrillus sphinx, an Old-World primate, exhibit specific behavioural strategies to avoid nematode infection. Our results show that individuals did not avoid faeces in a nonfeeding context but did avoid eating food items contaminated with faecal material, females more so than males. However, neither the presence of nematodes nor the age of faeces influenced the level of avoidance observed, suggesting that mandrills avoid faecal material in general rather than nematodes specifically when foraging.