Drone variation in susceptibility to deformed wing virus as a target for selection in honey bees (Apis mellifera)

A principle threat to honey bee health continues to be viral infections, which often compound with other abiotic and biotic stressors to reduce individual bee health and thus colony productivity and survival. Despite the significant impacts of viruses, there are no antiviral treatments available to bees. However, bees vary in their susceptibility to viral infection, and this variance can be used as a target for selection of virus resistant bees. To do this, we have screened the viral resistance of (haploid) male bees in two different honey bee populations, one from a commercial beekeeping operation that has exhibited some viral resistance and one from a research derived Varroa mite resistant population. We have defined resistance in this case as reduced replication and maintenance of low levels of Deformed wing virus (DWV) for 48 hours post-injection of adult drone honey bees. Proportion of bees that were considered resistant or susceptible to DWV infection differed across the two populations. Additional measures of drone quality, including thorax width and gene expression of targets associated with sperm quality and flight performance, will be discussed in relation to susceptibility to viral infection. Overall, this initial work shows promise in drone selection as a target for breeding for virus resistance in honey bees.