Immune Cell Production Is Targeted by Parasitoid Wasp Virulence in a Drosophila–Parasitoid Wasp Interaction

The interactions between Drosophila melanogaster and the parasitoid wasps that infect species provide an important model for understanding host–parasite relationships. Following infection, D. larvae mount a response in which immune cells (hemocytes) form capsule around wasp egg, then melanizes, leading to death of parasitoid. Previous studies have found host hemocyte load; number hemocytes available encapsulation response; production lamellocytes, infection induced type, are major determinants resistance. Parasitoids evolved various virulence mechanisms overcome host, including both active suppression by venom proteins passive evasive mechanisms. We identified previously undescribed species, Asobara sp. AsDen, utilizes mechanism hosts. AsDen inhibits expression msn, member JNK signaling pathway, plays role lamellocyte production. restricts lamellocytes as assayed cell morphology altered msn expression. Our findings suggest alters suppress immunity.