Fate of dermally applied miticides fluvalinate and amitraz within honey bee (Hymenoptera: Apidae) bodies.

Varroa mites, Varroa destructor Anderson & Trueman, are economically important pests of honey bees. Varroa mites are principally controlled within honey bee colonies using miticides. However, despite their importance in managing mite populations for apiculture, potential effects of miticides on honey bees are poorly understood. Using gas chromatography-flame ionization detection, we investigated concentrations, over variable time frames and within different body regions, of two commonly used miticides, tau-fluvalinate and amitraz, after dermal exposure to honey bees. We also quantified mortality of honey bees exposed to each miticide at both a low and high dose. Significant differences were observed in distributions of miticides among body regions. Within honey bee body parts, tau-fluvalinate was more readily absorbed and decreased in concentration more rapidly than amitraz. Mortality increased with higher dosages of miticides, and at higher dosages mortality was greater from fluvalinate than from amitraz. For individual honey bees, our results for rate of breakdown suggest that fluvalinate may be the preferred miticide for apiculturists, whereas our mortality results suggest that amitraz may be preferable. Either choice must be weighed against geographic variation in varroa resistance to each pesticide and attendant costs of parasitism.