Enzyme levels used to monitor pesticide resistance in Varroa jacobsoni

SUMMARY

The contingency of pesticide resistance in the mite Varroa jacobsoni Oudemans prompted this preliminary study, in which methodology for assaying levels of two detoxification systems, namely esterases and glutathione S-transferase (GST), was developed. The total esterolytic activity detected in post- mitochondrial fractions of a homogenized 200-mg sample of V. jacobsoni from 10 colonies was 0.0068 (OD) min⁻¹ μg⁻¹ protein. GST activity, expressed in μmol conjugate min⁻¹ μg⁻¹ protein was 0.260±0.21 in the post-mitochondrial supernatant and 0.646±0.48 in the cytosol. These results pertain only to mites obtained from a single experimental apiary of A. mellifera ligustica in Israel. The methodology and preliminary results obtained may be used for subsequent local or regional monitoring of enzyme levels associated with pesticide resistance in V. jacobsoni.

Keywords:

• Varroa jacobsoni
• pesticide resistance
• detoxification systems
• esterases
• glutathione S-transferase
• honey bees
• Apis mellifera