A behavior-manipulating virus relative as a source of adaptive genes for Drosophila parasitoids

Some species of parasitic wasps have domesticated viral machineries to deliver immunosuppressive factors to their hosts. Up to now, all described cases fall into the Ichneumonoidea superfamily, which only represents around 10% of hymenoptera diversity, raising the question of whether such domestication occurred outside this clade. Furthermore, the biology of the ancestral donor viruses is completely unknown. Since the 1980's, we know that Drosophila parasitoids belonging to the Leptopilina genus, which diverged from the Ichneumonoidea superfamily 225My ago, do produce immuno-suppressive virus-like structure in their reproductive apparatus. However, the viral origin of these structures has been the subject of debate. In this paper, we provide genomic and experimental evidence that those structures do derive from an ancestral virus endogenization event. Interestingly, its close relatives induce a behaviour manipulation in present-day wasps. Thus, we conclude that virus domestication is more prevalent than previously thought and that behaviour manipulation may have been instrumental in the birth of such associations.