The over wintering survival of highly Varroa destructor infested honey bee colonies determined to be hygienic using the liquid nitrogen freeze killed brood assay
A study was performed to test the over wintering survival of honey bee (Apis mellifera anatoliaca) colonies heavily infested with Varroa destructor which had been found to be ‘hygienic’ using a liquid nitrogen freeze killed brood assay. 563 colonies in 11 apiaries were screened for hygienic behaviour at different times of the season. Frames of bees were randomly exchanged among test colonies to equalize colony size and mite load. Double-selected hygienic and unselected control colonies were left to over winter to test for survival. Only two out of 25 colonies survived, and one of them was from the double-selected group and the other one from unselected control group. The results suggest that hygienic behaviour as determined by the freeze killed brood assay may not be a predictor of resistance to V. destructor.