Prevalence, geographic distribution, and transmission pathway of Camponotus yamaokai virus

The relationship between hosts and viruses is influenced by various factors. One potential factor is sociality. In social organisms such as ants, the interaction between hosts and viruses might differ from those of solitary organisms due to their unique ecology. We previously isolated a double-stranded RNA toti-like virus, Camponotus yamaokai virus (CYV), from the arboreal ant Camponotus yamaokai. The ant exhibits a polygynous colony structure with multiple queens and within-nest mating behaviors. Such unique ecological traits may have driven the evolution of a distinctive relationship with the virus. However, the biological characteristics of CYV have not been sufficiently studied. In this study, we investigated the biological characteristics of CYV through rearing experiments and field surveys. No horizontal transmission between workers and broods was detected, and there were no significant differences in prevalence between castes. CYV was detected at all seven locations surveyed, with prevalence ranging from 60–95%. The high CYV prevalence across the host's distribution range indicates that the geographical distribution of CYV aligns with that of its host. These results suggest that CYV has spread throughout the host population, primarily through vertical transmission.