What is the primary way Varroa mites affect honey bees?

Varroa mites predominantly impact honey bees by feeding on their bodily fluids, specifically targeting the lipid bodies, which serve as crucial energy reserves for the bees. This feeding behavior weakens the honey bees physically, making them more susceptible to diseases and increasing their mortality rates. The depletion of fat reserves can lead to reduced overall health and vitality in the bee population, ultimately affecting the entire colony's productivity and longevity.

The other options suggest benefits that are not associated with the presence of Varroa mites; instead of increasing honey production or improving the immune system, their presence is detrimental to bee health. In terms of colony dynamics, rather than promoting reproduction, the stress and health decline caused by Varroa mites can lead to weaker colonies that struggle to reproduce effectively.