“…Mesocosm experiments generally inflate initial species densities, thereby causing larger effect sizes than do natural field experiments (Gurevitch, Morrow, Wallace, & Walsh, 1992). The densities and interaction strengths present in sample date one represented a version of the theoretic scenario of a high density, spill-over event following introductions of insect and weed biological control agents that is posited to cause transient to permanent damage to non-target species (Lynch, Ives, Waage, Hochberg, & Thomas, 2002). In this study, despite high densities of the non-native, there was neither damage to the native herbivore through increased parasitism via apparent competition, nor local extirpation.…”