Bee viral dynamics in a Sierran wildflower system

Viruses are implicated in the losses of honeybees, and due to rapid mutation rates, are of the biggest spillover risks to native bees. Thus far there are over 30 RNA viruses found in bees, but we know little about their host breadth nor their dynamics. Migratory honeybee operations follow crop pollination events, spreading viruses across large distances. Afterwards, they are placed at stopover sites where they interact with native bees through co-foraging on floral resources and have the potential to expose them to viruses. For my research I work in Sierran meadows with high levels of bee diversity and low honeybee abundance. I work with commercial beekeepers to migrate hives to these meadows. This allows me to survey before and after arrival to see if honeybees bring viruses with them, if native bees already had viruses circulating before honeybee arrival, and if interspecies transmission is occurring. Using longitudinal sampling I compare virus communities throughout the summer of 2021 at sites with and without honey bees to explore the directionality of pathogen transmission. I have found that honeybees brought Deformed Wing Virus (DWV), Black Queen Cell Virus (BQCV), and Lake Sinai Virus (LSV) with them but initially lacked Sac Brood Virus (SBV). Bumblebees did not have DWV or LSV before honeybee arrival but were already infected with BQCV and SBV. SBV was never found in honeybee foragers throughout the rest of the season. This also has implications in the ability of this virus to successfully circulate in bumblebees without honeybees present.