Changes in reproduction of Varroa destructor after honey bee queens were exchanged between resistant and susceptible colonies

This study examines changes in reproduction and mortality of Varroa destructor when queens from stocks of honey bees (Apis mellifera L.) that differ in susceptibility to the mites were exchanged between colonies. Queens were selected for suppression of mite reproduction (SMRD). In two experiments uniform colonies of bees were established; half the colonies were given queens selected for SMRD, and half were given unselected queens. Queens were exchanged after 7 (experiment 1) and 13 weeks (experiment 2). The percentage of mites that had no progeny was determined for each colony at 5 times (2 before and 3 after exchanging queens). Mites that had no progeny included live and dead mites. Results showed (1) that reproduction of mites is suppressed by adding a queen selected for SMRD, and (2) that a mite population recovers its reproduction when a SMRD queen is replaced by an unselected queen. Selection of the SMRD trait can be reduced to counting only live mites that laid no eggs and dead mites