Concurrent evolution of random dispersal and habitat niche width in host-parasitoid systems

Antagonistic interactions like those between hosts and parasites or parasitoids or between predators and prey are important for many ecological and evolutionary processes. Here, we contrast the effect of commensalism and host-parasitoid interaction (complete fertility loss for infected host), on the concurrent evolution of host dispersal and habitat niche width. We assume that host habitat niche width is associated with a fertility trade-off; the wider the habitat niche, the lower the maximum fertility in optimal habitats. We implement a spatially explicit, individual-based one-host-one-guest metacommunity model (guest species are commensals or parasitoids) with landscape heterogeneity of a continuous habitat trait that affects the hostʹs fertility only. The antagonistic interaction model follows the Nicholson–Bailey equation. ed to commensalism, the host-parasitoid interaction promotes the evolution of higher dispersal probability in hosts and guests. In comparison to homogeneous landscapes, lower dispersal probabilities of both hosts and guests evolve in heterogeneous landscapes. Other than in homogeneous landscapes, parasitoids typically evolve higher dispersal probabilities than their hosts in heterogeneous landscapes. The effect of landscape heterogeneity on dispersal evolution depends on the magnitude of the habitat–fertility trade-off for hosts and the search efficiency of parasitoids. Moreover, depending on the habitat–fertility trade-off, antagonistic interactions may promote evolution of habitat niche width in hosts. Landscape structure affects the evolution of dispersal and habitat niche width in opposite ways: in clustered (autocorrelated) landscapes, dispersal probability evolves to higher, but habitat niche width to lower levels than in random landscapes.