Intraspecific competition is a major force in mediating population dynamics, fuelling adaptation, and potentially leading to evolutionary diversification. Among the evolutionary arms races between parasites, one of the most fundamental and intriguing behavioural adaptations and counter-adaptations are superparasitism and superparasitism avoidance. However, the underlying mechanisms and ecological contexts of these phenomena remain underexplored. Here, we apply the Drosophila parasite Leptopilina boulardi as a study system and find that this solitary endoparasitic wasp provokes a host escape response for superparasitism avoidance. We combine multi-omics and in vivo functional studies to characterize a small set of RhoGAP domain-containing genes that mediate the parasite’s manipulation of host escape behaviour by inducing reactive oxygen species in the host central nervous system. We further uncover an evolutionary scenario in which neofunctionalization and specialization gave rise to the novel role of RhoGAP domain in avoiding superparasitism, with an ancestral origin prior to the divergence between Leptopilina specialist and generalist species. Our study suggests that superparasitism avoidance is adaptive for a parasite and adds to our understanding of how the molecular manipulation of host behaviour has evolved in this system.

种内竞争是调节种群动态、促进适应并可能导致进化多样化的主要力量。在寄生虫之间的进化军备竞赛中，最基本和最有趣的行为适应和反适应之一是超级寄生和避免超级寄生。然而，这些现象的潜在机制和生态背景仍未得到充分探索。在这里，我们应用果蝇寄生虫Leptopilina boulardi作为一个研究系统，发现这种孤独的内寄生黄蜂会引发宿主逃避反应，以避免上寄生。我们结合多组学和体内功能研究来表征一小组包含 RhoGAP 结构域的基因，这些基因通过在宿主中枢神经系统中诱导活性氧来介导寄生虫对宿主逃逸行为的操纵。我们进一步揭示了一种进化情景，其中新功能化和专业化导致 RhoGAP 域在避免超级寄生中的新作用，其祖先起源于Leptopilina之间的分歧之前专家和通才物种。我们的研究表明，避免超级寄生虫对寄生虫具有适应性，并增加了我们对宿主行为的分子操纵如何在该系统中进化的理解。