Data from: Host use dynamics in a heterogeneous fitness landscape generates oscillations in host range and diversification

Colonization of novel hosts is thought to play an important role in
parasite diversification, yet little consensus has been achieved about the
macroevolutionary consequences of changes in host use. Here we offer a
mechanistic basis for the origins of parasite diversity by simulating
lineages evolved in silico. We describe an individual-based model in which
(i) parasites undergo sexual reproduction limited by genetic proximity,
(ii) hosts are uniformly distributed along a one-dimensional resource
gradient, and (iii) host use is determined by the interaction between the
phenotype of the parasite and a heterogeneous fitness landscape. We found
two main effects of host use on the evolution of a parasite lineage.
First, the colonization of a novel host allowed parasites to explore new
areas of the resource space, increasing phenotypic and genotypic
variation. Second, hosts produced heterogeneity in the parasite fitness
landscape, which led to reproductive isolation and therefore, speciation.
As a validation of the model, we analyzed empirical data from Nymphalidae
butterflies and their host plants. We then assessed the number of hosts
used by parasite lineages and the diversity of resources they encompass.
In both simulated and empirical systems, host diversity emerged as the
main predictor of parasite species richness.