Parasite sharing in wild ungulates and their predators: The effects of phylogeny, range overlap, and trophic links
Emerging infectious diseases (EIDs) have been recognized as a critical conservation, health, and economic issue. In order to predict reservoirs of potential future EIDs, it is necessary to understand the biological and ecological factors that promote or discourage the transmission of disease between species. One way of exploring this issue is to examine the parasite and disease communities of wild species and determine which factors are correlated with variation in the similarity of community species composition. Past studies have considered correlates of parasite community similarity in primates and carnivores, and found that in general phylogenetic relatedness, body mass, and range overlap explain much of the variation community similarity among host species. Here we consider correlates of parasite community similarity in wild ungulates. Using a recently updated ungulate supertree, range overlap derived from IUCN range shapefiles, trait data from PanTHERIA, and host-parasite co-occurrence data from the Global Mammal Parasite Database we test for the influence of phylogeny, range overlap, and trait similarity on patterns of community similarity among 115 species of hoofed mammal. We also consider whether the presence or absence of direct trophic links explains the proportion of known ungulate parasites that infect various carnivore species.
Phylogenetic distance was significantly negatively correlated with community similarity in ungulates, and explained similar amounts of variance in community similarity to what was shown in a previous study of carnivores. Body mass similarity was also significantly and positively correlated with community similarity, but explained much less variance in community similarity than in previous studies of other groups. Geographic range overlap was also positively correlated with community similarity and was a much stronger predictor than either phylogenetic distance or mass. When different groups of parasites (i.e., viruses, bacteria, arthropods and helminthes) are considered separately the relative influence of phylogeny, range overlap, and trait similarity on community similarity varied, but their rank order of importance tended to remain similar. Though we do not consider domestic ungulates directly, our results suggest that range overlap and phylogenetic affinity between wild species and domestic species could be more important than other factors in predicting which wild species might be in danger from diseases of domestic species and which wild species might harbor future EIDs of domestic species. Even after accounting for differences in sampling effort among carnivore species, carnivores that feed on ungulates appear to be infected by more known ungulate parasites than those that do not.