DOI: 10.5061/dryad.sf7m0cg87
title: Effect of host-switching on the ecological and evolutionary patterns of parasites

description: Speciation via host-switching is a macroevolutionary process that emerges
 from a microevolutionary dynamic where individual parasites switch hosts,
 establish a new association, and reduce reproductive contact with the
 original parasite lineage. Phylogenetic distance and geographic
 distribution of the hosts have been shown to be determinants of the
 capacity and opportunity of the parasite to change hosts. Although
 speciation via host-switching has been reported in many host-parasite
 systems, its dynamic on the individual, population and community levels is
 poorly understood. Here we propose a theoretical model to simulate
 parasite evolution considering host-switching events on the
 microevolutionary scale, taking into account the macroevolutionary history
 of the hosts, to evaluate how host-switching can affect ecological and
 evolutionary patterns of parasites in empirical communities at regional
 and local scales. In the model, parasite individuals can switch hosts
 under variable intensity and have their evolution driven by mutation and
 genetic drift. Mating is sexual and only individuals that are sufficiently
 similar can produce offspring. We assumed that parasite evolution occurs
 at the same evolutionary time scale as their hosts and that the intensity
 of host-switching decreases as the host species differentiate. Ecological
 and evolutionary patterns were characterised by the turnover of parasite
 species among host species, and parasite evolutionary tree imbalance
 respectively. We found a range of host-switching intensity that reproduces
 ecological and evolutionary patterns observed in empirical communities.
 Our results showed that turnover decreased as host-switching intensity
 increased, with low variation among the model replications. On the other
 hand, tree imbalance showed wide variation and non-monotonic tendency. We
 concluded that tree imbalance was sensitive to stochastic events, whereas
 turnover may be a good indicator of host-switching. We found that local
 communities corresponded to higher host-switching intensity when compared
 to regional communities, highlighting that spatial scale is a limitation
 for host-switching.
description: We propose a theoretical model to simulate parasite evolution considering host-switching events on the microevolutionary scale, taking into account the macroevolutionary history of the hosts, to evaluate how host-switching can affect ecological and evolutionary patterns of parasites in empirical communities at regional and local scales. In the model, parasite individuals can switch hosts under variable intensity and have their evolution driven by mutation and genetic drift. Mating is sexual and only individuals that are sufficiently similar can produce offspring. We assumed that parasite evolution occurs at the same evolutionary time scale as their hosts and that the intensity of host-switching decreases as the host species differentiate. Ecological and evolutionary patterns were characterised by the turnover of parasite species among host species, and parasite evolutionary tree imbalance respectively. 
description: Fortan and R.