In a context of global change, arctic ecosystems are exposed to deep modifications not only of the biology and ecology of endemic species but also of the interactions they may have with an increasing number of introduced species. This project attempts to assess in Svalbard, the impacts of global changes on aphids. These phytophagous insects are particularly relevant organisms for studies on the effects of global warming and biological invasion because 1) of their extreme sensitivity to micro- and macro- changes due to their spectacular rate of increase and phenotypic plasticity and 2) of their colonizing capacity conferred by their parthenogenetic mode of reproduction and their dispersal potential