Verreaux’s sifaka (Propithecus verreauxi) and ring-tailed lemur (Lemur catta) endoparasitism at the Bezà Mahafaly Special Reserve

As hosts, primate behavior is responsible for parasite avoidance and elimination as well as parasite acquisition and transmission among conspecifics. Thus, host behavior is largely responsible for the distribution of parasites in free - ranging populations. We examined the importance of host behavior in acquiring and avoiding parasites that use oral routes by comparing the behavior of sympatric Verreaux’s sifaka (Propithecus verreauxi) and ring - tailed lemurs (Lemur catta) inhabiting the Beza Mahafaly Special Reserve (BMSR) in Madagascar. For each species, two groups lived in a protected parcel and two groups lived in anthropogenically - disturbed forests. Analysis of 585 fecal samples revealed that the BMSR ring - tailed lemurs harbored six species of nematode worms and three species of protistan parasites. The sifaka harbored only two nematodes. Differences in richness and prevalence appear to be linked to host behavior and the ecological distribution of their parasites. To understand the interplay between behavioral mechanisms to avoid or transmit parasites, we analyzed 683 hours of behavioral observations. BMSR ring - tailed lemurs were observed on the ground significantly more than sifaka and this terrestrial substrate use provides greater opportunities for soil - transmitted parasites to acquire a host. Ring - tailed lemurs using the anthropogenically - disturbed forests harbored parasites not found in the groups inhabiting the protected parcel which they may be acquiring via coprophagy or contact with feces. The arboreality of sifaka allows them to evade most soil-transmitted endoparasites and the patterns of parasitism exhibited by sifaka living in the anthropogenically - disturbed forests did not deviate from the patterns observed among the sifaka living in the protected parcel.