From these two articles:
Recent research has uncovered a new way that Varroa destructor mites harm honey bees beyond the already known threats of depleting fat-body tissue and transmitting viruses. Typically, bees defend themselves not just from within, but also by coating their bodies in venom—specifically melittin, a major component of bee venom which acts as an antimicrobial, antifungal, and antiviral on their cuticle (outer surface).
The study shows that bees infested by Varroa mites have significantly lower levels of melittin on their external surfaces. This weakens their “venom shield,” reducing the effectiveness of this external immune defence. Without sufficient melittin coating, bees are more vulnerable to pathogens that attack from the outside.
This adds a third major mechanism by which Varroa mites harm bee colonies: besides draining bodily resources and spreading viral pathogens, they also degrade bees’ antimicrobial armor.
.png){kind=small}
