RT Journal Article SR Electronic T1 A Vertically and Horizontally Transmitted RNA Virus Facilitates Egg Hatching of a Parasitoid Wasp JF bioRxiv FD Cold Spring Harbor Laboratory SP 2024.10.30.621033 DO 10.1101/2024.10.30.621033 A1 Izraeli, Y. A1 Wodowski, G. A1 Mozes-Daube, N. A1 Varaldi, J. A1 Zchori-Fein, E. A1 Chiel, E. YR 2024 UL http://biorxiv.org/content/early/2024/10/30/2024.10.30.621033.abstract AB Information on the impacts of RNA viruses inhabiting insect hosts is scarce. Here, we studied the effects of a recently described RNA virus, termed AnvRV, on its host, the parasitoid wasp Anagyrus vladimiri (Hymenoptera: Encyrtidae), an important natural enemy of mealybug pests. AnvRV was found to be maternally transmitted with very high fidelity but not paternally. Additionally, AnvRV was horizontally transferred at an efficiency of 23% from infected to uninfected wasp larvae that develop together inside the same mealybug host (superparasitism). To test the effects of AnvRV on A. vladimiri, the virus horizontal transmission was utilized to establish AnvRV-infected (RV+) and uninfected (RV-) isogenic wasp lines, a method rarely applied and novel to RNA virus-parasitoid systems. Longevity, developmental time, sex ratio, and fecundity of RV+ and RV- A. vladimiri were very similar. Nonetheless, the egg hatching rate of RV+ wasps was markedly and significantly higher than that of RV- wasps, especially in hosts that were not superparasitized. Additionally, less encapsulation marks (the main form of mealybug immunity) were found around RV+ eggs inside parasitized mealybug hosts. Taken together, the data suggest that AnvRV is affecting the mealybugs’ physiology in a way that improves first stages of wasps’ development. These findings present a rare example of interaction between an RNA virus and a parasitoid and may provide a tool for the improvement of biological control efforts.Competing Interest StatementThe authors have declared no competing interest.