Recently published in Molecular Ecology (PDF available above), this article presents a novel method to describe the host specificity of pathogens by combining host species’ phylogenetic and functional distances into a single informative metric. Our method has a wide array of potential applications, and will be useful to improve our understanding of host-pathogen evolution and the future risks of disease emergence as pathogens shift hosts.
A variety of historical and contemporary mechanisms can lead to phylogenetic dispersion patterns of host use by parasites. Here we illustrate some of these on a hypothetical host phylogeny, where black shading indicates infection by a multi-host parasite.
This figure shows how closely related parasite assemblages are within individual host species. By comparing parasite phylogenetic distances to null expectations, we find that some hosts carry assemblages of closely related parasites, suggesting that only certain evolutionary groups of parasites are able to infect certain host species .