Attraction versus avoidance: honeybees vary in response to virus-contaminated food

Pathogen detection plays a key role in enabling hosts to avoid infection. Many insects, including honeybees (Apis mellifera, L.), can detect pathogens indirectly, but it is unclear whether they can directly detect viruses outside of a host. We conducted cage and field choice assays using unadulterated and virus-spiked sucrose solutions to assess detection and behavioural responses of honeybees to virus-contaminated foods. In cage trials, nurse-aged bees generally preferred unadulterated sucrose solution in the summer, but showed a significant preference for virus-spiked solutions containing deformed wing virus (DWV), black queen cell virus or chronic bee paralysis virus in the fall. In field trials, forager bees exhibited significantly higher visitation to, and consumption of, sucrose solutions with high concentrations of DWV compared to low DWV or virus-free controls in both the spring and fall. These findings demonstrate that honeybees can directly detect the presence of viruses in contaminated food sources, which has important implications for pathogen transmission within pollinator communities and disease management strategies aimed at improving honeybee health. However, the mechanisms underlying these phenomena remain unknown. Further research is needed to determine how virus presence alters honeybee behaviour and impacts social immune function, foraging behaviours and colony health.