Progress in proteomic marker-assisted selection for honey bees (Apis mellifera)

The Next-generation Integrated Pest Management Tools for Beekeeping (BeeIPM) project aims to demonstrate the efficacy of proteomic marker-assisted selection for enhancing resistance to brood diseases and parasitism by the mite Varroa destructor.  In 2011, 622 colonies were tested for hygienic behavior (HB) across four Canadian provinces.  A portion of these colonies was then randomly selected to establish an unselected benchmark population (n=83) as well as an F₀ population (n=110).  We successively tested, selected and propagated three generations from our F₀from 2011 to 2013, in a comparison of proteomic-based marker-assisted selection (MAS) against traditional behaviorally-based phenotypic selection (FAS) on HB.      

FAS-selected stock exhibited relative increases in hygienic behavior of 28.6, 19.9 and 31.7% over benchmark populations in the F₁- F₃ generations, respectively.  Similar, though smaller, gains were observed for the MAS-selected stock where levels of HB increased 10.6, 13.0, and 20.1 % over benchmark populations for the F₁ through the F₃.  Progeny for each generation were also evaluated for Varroa Sensitive Hygiene.  Overall, F₃ colonies showed a reduction in Varroa-infested brood of 38.8 ± 5.6% for FAS-selected stock and 40.2± 4.2 % for MAS-selected stock, compared with benchmark stock at 21.9 ± 3.9 %.  Nevertheless, the fertility of mites remaining in the brood remained unchanged for FAS and MAS selected stock over three generations (combined mean of  89.8 ± 1.1 %) , and similar to the benchmark population. 

Both FAS and MAS selected stocks were also evaluated via whole-colony challenge experiments with American foulbrood disease (AFB) and V. destructor.  Clear evidence of improved colony-level resistance to AFB was observed for FAS and MAS stocks in the F₁ and F₃ generations for several parameters, including the numbers of clinical symptoms of AFB in colonies over time, the proportion of colonies infected, as well as overwintering survival.   Resistance to V. destructor was associated with increased levels of hygienic behavior, lower mite infestations on adult bees and improved wintering survival.  Further results, including those relating to the economic performance of the selected stocks, will be discussed.

Our data are first to show the enrichment of disease and mite resistance using proteomic markers and the utility of this novel technology in bee breeding.