Abstract
A challenge for ecologists has been to understand how individual traits of organisms affect species interactions and community dynamics. Recent breakthroughs provide ecologists with exciting tools to address this through an ecogenomics approach. This allows delicate manipulative studies in which mechanistic knowledge of well-characterized genotypes and phenotypic plasticity can be exploited to study the effect of individual plant traits on interactions in ecosystems. Such an ecogenomic approach is the topic of this proposal. Food webs are overlaid with infochemical webs that mediate direct and indirect interactions. It is increasingly clear that indirect interactions can have important effects on community dynamics. Infochemicals are interesting in this respect because they cannot be directly used in body building, yet the responses they elicit have important consequences for fitness, and thus for interactions in a community. Infochemicals from plants influence interactions with members of different trophic levels, such as carnivores and herbivores. The infochemical-phenotype of plants is plastic: infochemical emission is an active and specific process that is induced by herbivory. The infochemicals attract carnivores that affect the herbivore population. Additionally, the infochemicals also affect herbivore behaviour and characteristics of neighbouring competitor plants. Careful manipulation of the phenotypically plastic emission by plants provides unique opportunities to investigate the effect of the infochemicals on food-web interactions. We will take this ecogenomic approach in field and laboratory studies for a system of crucifer plants (Brassica and Arabidopsis) and the related herbivorous and carnivorous insects (with a focus on Pieris butterflies and their Cotesia parasitoids). The tools (genotypes and phenotypic manipulation) have been developed and will be exploited to monitor (cDNA microarrays) and manipulate plant infochemical phenotype and investigate its effects on individual interactions in a food web in addition to a quantitative food web analysis. This novel approach creates an essential link between molecular, chemical, behavioural and community ecology.
Netherlands