Parasitoid wasps are exceptionally diverse and use specialized adaptations capable of manipulating the physiology and behaviour of host organisms¹. In more than two centuries since the first records of Drosophila-parasitizing wasps, nearly 200 described and provisional parasitoid species of drosophilids have been identified². These include endoparasitoids and ectoparasitoids, as well as species attacking larval and pupal hosts³. Despite a deep history of research attention and remarkable biodiversity, a wasp species that attacks and develops inside the adult stage of a fly host has not been described previously. Here we report the discovery of a wasp species that infects the adult stage of fruit flies in the genus Drosophila, including one of the most deeply studied model organisms in biology, Drosophila melanogaster. Notably, this wasp can be easily collected from backyard fly baits and has a broad geographic distribution throughout the eastern USA. We document its life history and unique host interactions, including egg-laying into and larval emergence from adult flies, and provide protocols to raise wasps from wild-caught host flies. Our results emphasize the need for ongoing research investment in insect biodiversity and systematics. As parasitoid research continues to uncover unusual biology and supports fundamental mechanistic insights into immunity⁴, metabolism⁵, ecology⁶, evolution^7,8,9 and behaviour^10,11,12, we anticipate that this wasp’s association with the laboratory model organism, D. melanogaster, will provide new research opportunities across the life sciences.

类寄生蜂非常多样化，并且使用能够操纵宿主生物体的生理和行为的特殊适应¹。自果蝇寄生蜂首次记录以来的两个多世纪里，已经确定了近 200 种已描述和临时的果蝇寄生物种²。这些包括内寄生虫和外寄生虫，以及攻击幼虫和蛹宿主^{的物种 3}。尽管研究关注的历史悠久且生物多样性显著，但以前从未描述过在苍蝇宿主成虫阶段攻击和发育的黄蜂物种。在这里，我们报告了一种黄蜂物种的发现，该物种感染果蝇属的果蝇成虫阶段，包括生物学中研究最深入的模式生物之一，黑腹果蝇。值得注意的是，这种黄蜂可以很容易地从后院的苍蝇饵中收集，并且在整个美国东部具有广泛的地理分布。我们记录了它的生活史和独特的宿主相互作用，包括成蝇的产卵和幼虫出现，并提供了从野生捕获的宿主苍蝇中饲养黄蜂的方案。我们的结果强调了对昆虫生物多样性和系统学进行持续研究投资的必要性。随着类寄生虫研究不断发现不寻常的生物学，并支持对免疫⁴、新陈代谢⁵、生态学⁶、进化^7、8、9 和行为^10、11、12 的基本机制见解，我们预计这种黄蜂与实验室模式生物黑腹果蝇的关联将为整个生命科学提供新的研究机会。