"The project aims at characterizing and comparing food webs associated with aphids developing on 6 distinct ecosystems in native vs. invaded areas (continents). By considering food webs associated with pest insects and comparing food web structure & functioning on an international scale, we will broaden our understanding of processes underpinning food web functioning and herbivore population regulation. We will also document structural and functional changes owing to migration or invasion processes. Comparison of food webs in native and invaded regions will also focus on factors structuring trophic networks associated with aphid pests in various ecosystems worldwide.The key actions will be to:(1) Develop molecular identification techniques to detect trophic links in field collected samples. Ease of implementation should be aimed at(2) Create food webs: quantify trophic links between aphids, their natural enemies and other key species. Standardized sampling protocols will be used in the various ecosystems at various locations worldwide(3) Use existing food web analysis methods and develop new ones to quantify changes in food webs on an international scale(4) Investigate determinants and mechanisms affecting the outcome of invasion (or introduction for classical biological control) of aphid-associated alien speciesThe scope of potential results of the project is wide. Aphids being a worldwide pest, food web studies can provide crucial data for biological control applications, from classical to conservation approaches. The international scale of the study will enable investigating biogeographic hypotheses, which are a valuable contribution to ecological theory but are also applicable to biosecurity, e.g. safety of classical biological control programs for endemic biodiversity. Possible additional local scale comparisons and studies would provide information documenting theories on apparent competition, host range, specialization and their effects on trophic levels"