Wu Zhiwei, Wu Xiaotong, Wang Zhizhi, Ye Xiqian, Pang Lan, Wang Yanping, Zhou Yuenan, Chen Ting, Zhou Sicong, Wang Zehua, Sheng Yifeng, Zhang Qichao, Chen Jiani, Tang Pu, Shen Xingxing, Huang Jianhua, Drezen Jean-Michel, Strand Michael R, Chen Xuexin
Zhejiang Engineering Research Center for Biological Control of Crop Pathogens and Insects, Zhejiang Key Laboratory of Biology and Ecological Regulation of Crop Pathogens and Insects, Ministry of Agriculture and Rural Affairs Key Lab of Molecular Biology of Crop Pathogens and Insect Pests, State Key Lab of Rice Biology and Breeding, Institute of Insect Sciences, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China.
Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS - Université de Tours, Tours 37200, France.
Proc Natl Acad Sci U S A. 2025 May 6;122(18):e2422935122. doi: 10.1073/pnas.2422935122. Epub 2025 Apr 28.
Animals often exhibit increased aggression in response to starvation, while parasites often manipulate host behavior. In contrast, underlying molecular mechanisms for these behavioral changes are mostly unknown. The diamondback moth, , is an agricultural pest that feeds on cruciferous plants as larvae, while is a parasitoid wasp that parasitizes diamondback moth larvae. In this study, we determined that unparasitized diamondback moth larvae exhibit increased aggression and cannibalism when starved, while starved larvae parasitized by were more aggressive than unparasitized larvae. harbors a domesticated endogenized virus named Cotesia vestalis bracovirus (CvBV) that wasps inject into parasitized hosts. Starvation increased octopamine (OA) levels in the central nervous system (CNS) of diamondback moth larvae while a series of experiments identified a CvBV-encoded gene product named Assailant that further increased aggression in starved diamondback moth larvae. We determined that Assailant increases OA levels by activating (), which is a key enzyme in the OA biosynthesis pathway. Ectopic expression of in likewise upregulated expression of and OA, which increased aggressive behavior in male flies as measured by a well-established assay. While parasitized hosts are often thought to be at a competitive disadvantage to nonparasitized individuals, our results uncover how a parasitoid uses an endogenized virus to increase host aggression and enhance survival of offspring when competing against unparasitized hosts.
动物通常会因饥饿而表现出攻击性增强，而寄生虫常常会操纵宿主的行为。相比之下，这些行为变化背后的分子机制大多尚不为人知。小菜蛾是一种农业害虫，其幼虫以十字花科植物为食，而菜蛾盘绒茧蜂是一种寄生蜂，会寄生小菜蛾幼虫。在本研究中，我们发现未被寄生的小菜蛾幼虫在饥饿时会表现出更强的攻击性和同类相食行为，而被菜蛾盘绒茧蜂寄生的饥饿幼虫比未被寄生的幼虫更具攻击性。菜蛾盘绒茧蜂携带一种名为菜蛾盘绒茧蜂内源性病毒（CvBV）的驯化内源性病毒，寄生蜂会将其注入被寄生的宿主体内。饥饿会增加小菜蛾幼虫中枢神经系统（CNS）中的章鱼胺（OA）水平，而一系列实验确定了一种名为攻击者的CvBV编码基因产物，它会进一步增强饥饿小菜蛾幼虫的攻击性。我们确定攻击者通过激活OA生物合成途径中的关键酶酪氨酸羟化酶（TH）来增加OA水平。在果蝇中异位表达TH同样会上调TH和OA的表达，通过一种成熟的测定方法测量，这增加了雄蝇的攻击性行为。虽然通常认为被寄生的宿主相对于未被寄生的个体处于竞争劣势，但我们的结果揭示了一种寄生蜂如何利用内源性病毒在与未被寄生的宿主竞争时增加宿主的攻击性并提高后代的存活率。
