The effects of metapopulation structure on indirect interactions in host-parasitoid assemblages

The interaction between two species that do not compete for resources but s hare a common natural enemy is known as apparent competition. In tho absenc e of other limiting factors, such three-species interactions are impermanen t, with one species being excluded from the assemblage by thr natural enemy . Here, the effects of metapopulation structure are explored in a system of two hosts that experience apparent competition through a shared parasitoid . A coupled-map lattice model is developed and used re, explore species coe xistence and patterns of patch occupancy at the metapopulation scale. Linki ng local and regional dynamics favours coexistence by uncoupling the dynami cs of the. three species in space Coexistence is promoted by the inferior s pecies being either a fugitive or a sedentary species. The occurrence of th ese two mutually exclusive mechanisms of coexistence is influenced by the r elative dispersal of the inferior apparent competitor.