From the perspective of a parasite, each potential host is an ecosystem waiting to be colonized. As parasites contribute to the stability and functioning of aquatic ecosystems, it is necessary to develop a holistic knowledge of the drivers of parasite community structure within their hosts. Determinants of parasite community structure within each host are difficult to ascertain, with multiple potential drivers of the abundance and diversity of parasites interacting to shape the community. In addition to environment- and host-level influences, parasites can compete within hosts, facilitate other parasitic infections within hosts, or not interact with other parasites. The hierarchical modelling of species communities (HMSC) framework has effectively determined the effects of these complicated, multi-level drivers on parasitic communities within rodent hosts, revealing predominantly positive associations among parasites. However, parasite communities within endothermic mammals differ from the communities within ectothermic hosts, and it is unknown whether these positive associations among parasites will be found within ectothermic hosts. Here, we use a HMSC framework to determine the association patterns among more than 50 parasite taxa within 7 coral reef fish hosts from the Northern Line Islands, an archipelago of coral islands in the central equatorial Pacific.
Results/Conclusions
The results presented here highlight the potential utility of HMSC frameworks in determining drivers of parasite species co-occurrence patterns, with potential future applications within disease ecology, epidemiology, and parasitology. The parasitic community within coral reef fishes was dominated by a few taxa, most of which were localized within fins, gills, and intestinal tissues. The majority of associations found among parasites within their hosts were positive, meaning that infection by one parasite taxon increased the probability of being infected by other parasites. Though the particular species parasitizing ectothermic fishes and endothermic mammals may differ, the general trend towards positive interactions among parasites suggest that these interactions are likely crucial to parasite community structure across many host taxa.