CAN WE PRODUCE VARROA-TOLERANT HONEY-BEES IN THE UNITED-STATES

This two-year study was undertaken to determine whether a varroa-toler ant honey bee population could be developed and maintained via selecti ve breeding and conventional beekeeping practices without the use of o ther mite control strategies. Colonies (or queens therefrom) surviving in untreated apiaries, or with noteworthy low varroa infestation leve ls, were obtained from several cooperating beekeepers across southern and central Arizona. These were moved to the study site which consiste d of a cluster of three isolated apiaries located in southeastern Ariz ona. The colonies/queens were installed in the central apiary. The two outlying apiaries were requeened with daughter queens grafted from su rvivor colonies with the lowest parasite infestations and were open-ma ted in the central apiary. Colonies which subsequently developed high mite infestations were requeened or removed from the study. Tracheal a nd varroa mite populations on adult bees were determined every two mon ths throughout the study. The two year mean and range for varroa infes tation levels was 6.8 (0-50.3) mites/100 bees. The mean and range for bees infested with tracheal mites was 4.9% (0-50%). There was no signi ficant interaction between varroa and tracheal mite infestations. We f ound it relatively easy to find varroa-tolerant colonies. Our results demonstrate that it is indeed possible to produce and maintain varroa- tolerant strains of honey bees out of domestic stock. Corroborating da ta from collateral studies clearly show that some beekeepers/bee breed ers are currently doing just that. Concurrent data obtained from a stu dy of feral colonies in Arizona also show a change toward varroa-toler ance.