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RESEARCH PRODUCT

Should grape moth larval immunity help explaining resistance against natural enemies?

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National audience; In tritrophic systems (plants, phytophagous insects and natural enemies), host plant variation often keys the relative performance of both the herbivore and its associated natural enemies. In bottom-up effects, host plants could affect the fitness of phytophagous insects including growth rate and adult fertility. These effects are indirectly reflected in parasitoids whose success depends on their host quality. For instance, nutrient deficiency or/and toxic defensive compounds of the plants could slow-down the development of herbivorous insects, thus extending the window of vulnerability of attacks by natural enemies. The immune system is arguably the most common resistance mechanisms used by phytophagous insects against natural enemies such as parasites and parasitoids. However, only a limited number of studies have really linked tritrophic interactions and immune defenses of phytophagous insects. Our work considers two grape moths, the European grapevine moth, Lobesia botrana, and the European grapeberry moth Eupoecilia ambiguella. In this study, we have tested the influence of different grapevine varieties on the baseline level of three immune parameters (concentration of haemocytes, activity of the prophenoloxidase system and antimicrobial activity) of larvae of the European grapevine moth. In this presentation we discuss the results obtained in this experiment and their effects and importance in tritrophic.