How does deformed wing virus harm honeybees?

Deformed wing virus (DWV) is a significant pathogen transmitted to honeybees primarily by the parasitic varroa mite.12

The virus harms bees by causing physical malformations in their wings, bodies, and legs. These deformities often result in more severe damage to the individual bee than the direct feeding of the mites themselves. By weakening the bees and compromising their health, the virus makes colonies more susceptible to colony collapse disorder (CCD).21

Furthermore, environmental stressors can exacerbate the impact of the virus. For instance, exposure to certain pesticides, such as imidacloprid and clothianidin, may suppress the immune function of bees and promote the proliferation of deformed wing virus within the colony. While DWV is frequently found in hives affected by CCD, researchers have not definitively identified it as the sole cause of the disorder, suggesting instead that it acts as one of many potential stressors in a complex, synergistic decline.2