RNA Viruses Associated with Parasitoid Wasps: Diversity, Transmission, Biological Functions, and Implications for Biological Control

Parasitoid wasps are ecologically important natural enemies and widely used biological control agents. Although virus research in parasitoids has historically focused on polydnaviruses and other DNA viruses, advances in high-throughput sequencing and metaviromics have revealed an unexpectedly diverse assemblage of parasitoid-associated RNA viruses. These viruses include positive-sense single-stranded RNA, negative-sense single-stranded RNA, and double-stranded RNA viruses distributed across numerous parasitoid lineages. This review synthesizes current knowledge of the diversity, transmission strategies, and biological functions of RNA viruses associated with parasitoid wasps. It further evaluates their potential significance for mass rearing, colony quality management, and biological control. Although most reported viruses remain functionally uncharacterized and current evidence is largely laboratory-based, emerging findings suggest that some RNA viruses establish persistent associations that alter parasitoid traits and parasitoid–host interactions. Future research integrating metaviromics, functional genomics, reverse genetics, and field ecology will be essential to determine whether beneficial viral associations can be reliably incorporated into sustainable pest-management programs.