Spatial patterns in host-parasite interaction networks

Distance-decay relationships -- where increasing geographic space between communities results in higher compositional dissimilarity between communities -- are a common observation in ecological communities of free-living species, and much less common for parasitic species. Here, we use a global database of helminth parasite occurrence records to examine spatial distance-decay patterns for host and parasite communities, as well as for the structure host-parasite interaction networks as a whole. Large scale patterns of parasite diversity should also incorporate data on host diversity, and one potential way forward is to treat host-parasite networks as sampling units.