Date of Award
Master of Science
Honey bee population decline has been attributed to a variety of causes including infestation of hives with Varroa destructor mites. Fluvalinate has been extensively used in the United States to combat these mites for nearly 30 years, despite its high toxicity to honey bees. The objectives of the current research project were to investigate the extent of fluvalinate contamination in commercially available wax and to define exposure pathways from the contaminated wax and fluvalinate-impregnated strips to larval and adult honey bees. All of the commercial wax tested in the current study contained elevated fluvalinate concentrations, ranging from 170 to 1040 ng/g wet weight, indicating a need for regulation of the sources of wax being rendered for resale. Based on the negative logarithm of the partition coefficient between wax and pollen (-0.54) and the fact that all of the tested wax samples contained elevated concentrations of fluvalinate, it is evident that fluvalinate has the potential to actively transfer from the contaminated wax into bee hive matrices. This point was confirmed by adding fluvalinate-dosed wax, fluvalinate-impregnated strips, or a combination of the two to 10-frame hives. Larvae and adult bees from those hives were checked for fluvalinate exposure using gas chromatography-mass spectrometry analysis. Larvae had detectable concentrations of fluvalinate in all three treatments. Bioaccumulation in adult bees was significantly affected by the interaction between treatment type and application time. In other words, residues were comparable from hives that only had fluvalinate-dosed wax to those that were actively being treated with impregnated strips, strongly suggesting that transfer of fluvalinate from wax into adult bees was an important exposure route. In conclusion, exposure of fluvalinate from contaminated wax and treatment strips to larvae and adult honey bees is an important factor that needs to be considered when applying miticides and evaluating risk in honey bee hives.
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