> How do varroa mites affect honey bees? Several avenues have been proposed. First, varroa mites immunosuppress honey bees. Second, the mites live on bee haemolymph, which may cause reduced adult body weight and protein content. Third, varroa mites are implicated in many bee diseases. The mites are blamed for causing a so-called parasitic-mite syndrome. More importantly, the mites have been suggested and demonstrated to vector various bee viruses.

> It has become clear that varroa mites have a keystone role in this four-way interaction between bees, mites, viruses and microbes. Clarifying the role of varroa mites in bee survivorship is needed given this complex interaction. Is the death of bee colonies
only due to the interaction between bee immunosuppression and
pathogens or are impacts of the mite parasitization on physiological
traits also involved?

> Our results suggest that the primary cause of bee death and colony collapse may be due to the immunosuppression of the bees by the varroa mites and the continued impact on the adult bees. We are currently exploring the correlation between varroa mite parasitization,
virus infections, and microbial exposure.

from:
Effects of parasitization by Varroa destructor on survivorship and
physiological traits of Apis mellifera in correlation with viral
incidence and microbial challenge

by:
X. YANG and D. COX-FOSTER
Parasitology 134(3):405 (2007)

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