RNA virus diversity in three parasitoid wasps of tephritid flies: insights from novel and known species

Parasitoid wasps are a diverse group of parasitoid insects that play a crucial role in biological control and integrated pest management programs due to their wide range of host species and complex behaviors. Previous studies have reported that select RNA viruses in parasitoid wasps can affect either the host-parasitoid wasp or the pest host parasitized by the wasps. Therefore, a study of the dynamics of RNA viruses in parasitoid wasps is essential for artificial breeding programs and improving their parasitic capabilities. In this study, we detected the presence of nine novel and three known RNA viruses with complete genomes in three parasitoid wasp species: Diachasmimorpha longicaudata, Fopius arisanus, and Spalangia endius. These wasps are parasitoids that can parasitel tephritid flies, one of the most important pest groups of fruits and vegetables. In D. longicaudata, the small RNAs derived from the viruses exhibited distinct peaks at 22 nt and were symmetrically distributed across the viral genome. These findings indicate that these viruses can activate the host's RNAi immune response. PCR detection further revealed that DlNaLV efficiently infects female individuals of D. longicaudata with 100% efficiency, and ZcNLV is capable of infecting both D. longicaudata and its host, Zeugodacus cucurbitae. Our findings contribute to a better understanding of RNA viruses in parasitoid wasps and lay the foundation for future research on the triple-level trophic relationships between tephritid flies, parasitoid wasps, and RNA viruses.IMPORTANCEParasitoid wasp populations have developed persistent beneficial symbiotic relationships with several viruses through repeated evolution. However, there have been limited reports on RNA viruses in parasitoid wasps of tephritid flies, a significant pest group affecting fruits and vegetables. This study explores the diversity of RNA viruses in three parasitoid wasps of tephritid flies and highlights the potential biological significance of specific viruses in Diachasmimorpha longicaudata. These findings have important implications for the development of sustainable pest management strategies and the enhancement of artificial rearing techniques for parasitoid wasps. Parasitoid wasp populations have developed persistent beneficial symbiotic relationships with several viruses through repeated evolution. However, there have been limited reports on RNA viruses in parasitoid wasps of tephritid flies, a significant pest group affecting fruits and vegetables. This study explores the diversity of RNA viruses in three parasitoid wasps of tephritid flies and highlights the potential biological significance of specific viruses in Diachasmimorpha longicaudata. These findings have important implications for the development of sustainable pest management strategies and the enhancement of artificial rearing techniques for parasitoid wasps.