Individual plants harbour species rich communities of insects. These communities are structured by trophic interactions of who eats whom, but are also riddled with indirect interactions. One type of these interactions is mediated by the plant. In response to attack by one herbivore the plant changes its phenotype. Each community member may respond differently to this new phenotype and thus induced responses to one herbivore may alter community composition on the individual plant. I study how predictable these indirect interactions are for insect community structure and assess the importance of these processes in the evolution of (induced) plant defence.