Effect of Host-Switching on the Ecological and Evolutionary Patterns of Parasites.

This article focuses on modeling speciation in parasites via host-switching, a process where individual parasites switch to new host species, potentially leading to reproductive isolation and diversification. The authors developed an individual-based theoretical model that simulates parasite evolution on a microevolutionary scale while incorporating the macroevolutionary history of hosts, assuming that the probability of host-switching decreases with increasing phylogenetic distance between hosts. Using empirical host-parasite communities from various taxa and spatial scales, the model showed that host-switching intensity influences ecological patterns (parasite species turnover among hosts) and evolutionary patterns (parasite phylogenetic tree imbalance), with turnover decreasing as host-switching intensity increases. The study found higher host-switching intensities in local-scale communities compared to regional ones, highlighting spatial scale as a key factor in parasite diversification through host-switching.