Resistance to Acarapis woodi by honey bees (Hymenoptera : Apidae): Divergent selection and evaluation of selection progress

Two generations of hone, bees, Apis mellifera L., selected for resistance t o tracheal mites, Acarapis woodi (Rennie),were produced from a foundation s tock. The mite resistant lines had significantly low mite abundances and pr evalences in each selected generation. The high mite-resistant lines of the first selected generation showed resistance equal to that of bees that had undergone natural selection from tracheal mite infestations for 3 yr in Ne w York. Additionally, the high mite-resistant lines of the second selected generation and Buckfast bees had significantly lower mite abundances and pr evalences than honey bees from control colonies which had never been expose d to tracheal mite infestation in Ontario. These results corroborate studie s that have shown that honey bees possess genetic components for tracheal m ite resistance that can be readily enhanced in a breeding program. The two methods used for evaluating relative resistance of honey bees to tracheal m ites, a short-term bioassay and evaluation in field colonies, were positive ly correlated (r(s) = 0.64, P < 0.001).