The first aim of this project is the study of the parasitoid guild on one family of Chrysomelidae (Cassidinae on Concolvulacea) in relation to host plant specificity. The study will focus on 1) a species inventory and a comparison of guilds in relation with host specificity and plant defence, 2) the study of hyper and multiparasitism, 3) for the most abundant parasitoid species, an analysis of their life cycle and their specificity, 4) the comparative phylogeny of Cassidinae and their parasitoids. The second aim is the description of the tritrophic relation between Host-plants - Hispinae (Coleoptera, Chrysomelidae) - parasitoids and to analyse the food-web.