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

AO_SCPLOWBSTRACTC_SCPLOWIncreasing empirical evidence has revealed that host-switching are common in the history of parasites. Still, few have explored how the evolutionary histories of hosts might influence such switches and then the evolution of parasites. Here, we investigated how the intensity of host-switching, assumed to depend on the phylogenetic distance between hosts, affects the ecological and evolutionary patterns of parasite species. We developed an individual-based model where parasites can explore and colonise hosts under variable host-switching intensity and have evolution driven by mutation, genetic drift, and mating restriction. We hypothesised that our model can reproduce ecological and evolutionary patterns of empirical communities, characterised by turnover among host species and tree imbalance, respectively. We found an optimum range of host-switching intensity that can predict similar patterns as those observed in the empirical studies, validating our hypothesis. Our results showed that the turnover decreased as the host-switching intensity increased with low variation among the model replications. On the other hand, the tree imbalance had not a monotonic tendency but a wide variation. These results revealed that while the tree imbalance is a sensitive metric to stochastic events, the turnover may be a proxy for host switching. Furthermore, local empirical studies corresponded to higher host-switching intensity when compared to regional studies, highlighting that spatial scale is probably the crucial limitation of host-switching.