Body size, diet and sociality influence the species richness of parasitic worms in anthropoid primates

Free-ranging animals are exposed to a diverse array of parasitic worms, including nematodes, trematodes, cestodes and acanthocephalans. Across host species, the number and types of parasite species are expected to depend on both host and parasite characteristics. We focused on helminth communities reported from free-living anthropoid primates to investigate factors associated with parasite diversity in a single host clade. We used a comparative data set of 305 host-parasite combinations representing 69 anthropoid primate species and 136 parasite species based on records obtained from the Host-Parasite Database at the Natural History Museum, London. We examined four sets of host characteristics that are predicted to influence parasite diversity in primates: host body size and life history; social contact and population density; diet; and individual ranging behaviour. We controlled for effects of uneven sampling effort on per-host measures of parasite diversity and repeated analyses with and without controlling for host phylogeny. In tests that did not control for host phylogeny, a large number of predictor variables were significantly associated with the diversity of both total helminths and nematode parasites, including body size, life-history variables and day range length. However, multivariate tests revealed that body mass and, to a lesser extent, social group size accounted for most variation in parasite species richness. Analyses that controlled for host phylogeny using independent contrasts showed that diet (estimated as the percentage of leaves in diet) was positively associated with total helminth and nematode parasite diversity in analyses that excluded outliers. Individual ranging behaviour was positively associated with the diversity of parasites with complex life cycles, including cestodes, trematodes and acanthocephalans. Our results demonstrate that several key features of host biology are likely to influence the community diversity of helminths in wild primate populations, including body size, diet, sociality and ranging behaviour.

Duke Scholars

Author Charles L Nunn Evolutionary Anthropology