Herbivore feeding induces massive metabolic reconfigurations in plants under attack. Such changes mediate tissue repair, resource allocation and defence. Induced plant-defences are studied intensively since they are plant-own and thus might lead to novel and environment-friendly ways of crop protection. Induced plant-defences come in two forms: the first are the induced direct defences which involve plant-produced toxins. The second are the indirect defences which augment direct defences and are established by de novo production of herbivore-induced plant volatiles (HIPV) that attract natural enemies of herbivores. Both types of defence decrease herbivore fecundity and survival. Thus, plant defences must impose selection pressure on herbivores and natural selection theory predicts that species will undergo adaptive changes towards increased resistance, provided there is sufficient genetic variation. Recently, such intraspecific variability was described for the first time in a herbivorous pest, the spider mite Tetranychus urticae. It was found that different individuals can induce or suppress direct defences and, importantly, differentially induce the emission of HIPV. Therefore mites may not only adapt to become resistant to plant defences, but also to not induce them and to not induce the attraction of natural enemies. I propose to characterize T. urticae selection-lines that differ in the extent to which they induce direct and indirect defences, and (1) to elucidate mechanisms whereby they hinder direct and indirect defences; (2) to map the inheritance of traits that enable mites to hinder defences, and (3) to investigate the implication of such traits for the stability and persistence of predator-prey meta-populations. Meeting these objectives will shed new light on the mechanisms by which interactions between individual traits explain the macroscopic patterns in population dynamics and show new ways for sustainable pest-management.
Call for proposal
See other projects for this call