The world is green despite numerous herbivores. Coley & Barone (Ann. Rev. Ecol. Syst. 1996, 305- 335) estimated that c. 10% of the green biomass is consumed by herbivores. This equals the amount of resources that plants on average allocate to generative reproduction. Plants defend themselves in different ways to the armada of herbivores. Well known are the morphological and chemical defences (mostly secondary metabolites) employed by plants. If these defences are not effective plants can sometimes tolerate herbivory (e.g. regrowth capacity after defoliation) or rely on the association with other species like toxin-producing endophytic symbionts or attracting natural enemies of the attacking herbivores.