Effect of host-switching on the eco-evolutionary patterns of parasites

Increasing empirical evidence has revealed that host-switching is more common than cospeciation in the history of parasites. Here, we investigated how the intensity of host-switching, mediated by opportunity and compatibility, affects the phylogenetic history and ecology of the parasites. We developed a theoretical model to simulate the evolution of populations of parasites that can explore and colonize new hosts under variable host-switching intensities. Eco-evolutionary patterns (beta diversity/normalized Sackin index) obtained from parasite simulations were compared to nine empirical cases. Our model reproduced the empirical patterns, and such simulations varied in host-switching intensity according to the analysed case. This intensity does not differ among cases of ecto and endoparasites, but it was stronger in local cases when compared to a regional scale. Our results highlight the importance of contact opportunity, and suggest that host-switching intensity mediates the exploration and colonization of new hosts promoting variation in the eco-evolutionary patterns.