Haemolymph defence of an invasive herbivore: its breadth of effectiveness against predators

Invasive insects have profound and lasting effects on the food webs of recipient habitats, and how food webs respond to the introduction of an exotic species has important implications for the ultimate establishment and integration of these invasives. One way that resident food webs confront invasion by exotic species is through biotic resistance, in part through predation of the invader (Parker et al. 2006; Nunez et al. 2008; Harwood et al. 2009). The success of an invader depends in part on its defensive capabilities against predation. But, predator diversity within even the most disturbed subterranean arthropod communities is significant (Duelli and Obrist 1998; Downie et al. 1999; Duelli et al. 1999; Lundgren et al. 2006, 2009b; Juen and Traugott 2007), and predators rely differentially on a given herbivore within these systems. Thus, a key aspect of the invasion process is how predator constituents of a food web are relatively affected by the defensive capabilities of an invasive pest.