Possible Spillover of Pathogens between Bee Communities Foraging on the Same Floral Resource.

Viruses are known to contribute to bee population decline. Possible spillover is suspected from the co-occurrence of viruses in wild bees and honey bees. In order to study the risk of virus transmission between wild and managed bee species sharing the same floral resource, we tried to maximize the possible cross-infections using which is highly attractive to honey bees and a broad range of wild bee species. Virus prevalence was compared over two years in Southern France. A total of 1137 wild bees from 29 wild bee species (based on COI barcoding) and 920 honey bees () were checked for the seven most common honey bee RNA viruses. Halictid bees were the most abundant. Co-infections were frequent, and (SBV), (BQCV), (ABPV) and (IAPV) were widespread in the hymenopteran pollinator community. Conversely, (DWV) was detected at low levels in wild bees, whereas it was highly prevalent in honey bees (78.3% of the samples). Both wild bee and honey bee virus isolates were sequenced to look for possible host-specificity or geographical structuring. ABPV phylogeny suggested a specific cluster for bees, while isolates of DWV from bumble bees ( spp.) clustered together with honey bee isolates, suggesting a possible spillover.