Next generation sequencing study on RNA viruses of Vespa velutina and Apis mellifera sharing the same foraging area

The predator Asian hornet (Vespa velutina) represents one of the major threats to honeybee survival. Viral spillover from bee to wasp has been supposed in several studies, and this work aims to identify and study the virome of both insect species living simultaneously in the same foraging area. Transcriptomic analysis was performed on V. velutina and Apis mellifera samples, and replicative form of detected viruses was carried out by strand-specific RT-PCR. Overall, 6 and 9 different viral types were reported in V. velutina and A. mellifera, respectively, and five of these viruses were recorded in both hosts. Varroa destructor virus-1 and Cripavirus NB-1/2011/HUN (now classified as Triato-like virus) were the most represented viruses detected in both hosts, also in replicative form. In this investigation, Triato-like virus, as well as Aphis gossypii virus and Nora virus, was detected for the first time in honeybees. Concerning V. velutina, we report for the first time the recently detected honeybee La Jolla virus. A general high homology rate between genomes of shared viruses between V. velutina and A. mellifera suggests the efficient transmission of the virus from bee to wasp. In conclusion, our findings highlight the presence of several known and newly reported RNA viruses infecting A. mellifera and V. velutina. This confirms the environment role as an important source of infection and indicates the possibility of spillover from prey to predator.