Virus-specific impacts on honey bee flight performance are mediated by the octopamine pathway

High annual losses of honey bee colonies can be traced back to environmental and biological stressors like virus infections. The octopamine (OA) pathway in insects, responsible for the 'fight-or-flight' response, influences energy mobilization, temperature, and flight. Researchers discovered that sacbrood virus (SBV) infections boost honey flight performance, while deformed wing virus (DWV) infections hinder it. However, the specifics of how these viruses interact with the OA pathway were unclear.

To investigate, honey bees were infected with either SBV or DWV and exposed to OA, an OA receptor antagonist called epinastine (EP), or a combination of both OA and EP. The study then assessed their flight capabilities and gene expression. Manipulating the OA system showed that adding OA compensated for the flight deficits in DWV-infected bees but decreased performance in SBV-infected bees. Blocking OA receptors, on the other hand, altered these outcomes.

Genomic analysis revealed that SBV infections, along with DWV infections when treated with OA, activated metabolic pathways in honey bees. SBV-infected bees showed a higher expression of genes linked to OA synthesis, unless given OA treatment. This research offers a deeper understanding of how specific viruses can affect honey bee flight, which could have implications for the bees' foraging efficiency, overall health, and virus transmission rates.