Great step forward in breeding Varroa Resistant Honeybees
Boxmeer, February 12, 2015. Honey bee populations worldwide, important for pollination of our food crops, are being challenged by a highly damaging mite: Varroa destructor. In an effort coordinated by the Arista Bee Research Foundation a group of European beekeepers has, during last spring and summer, bred a first generation of European honey bees that can detect the Varroa mite, clean out infested brood and by doing so are expected to keep the number of Varroa mites under control. This is an important step in breeding healthier, Varroa resistant honey bees that can much better survive in an already challenging environment.
The Varroa mite creates a hole in the armor of the bee and directly weakens the bee by sucking out hemolymph (“insect blood”). In addition, viruses and bacteria can now enter through this hole causing diseases and even an early death of the bee. Chemical treatments are used on colonies, but this is laborious, has variable results, can leave residues and does not only effect the mites but can also harm the bees. Untreated colonies often collapse within 2 years from the consequences of the fast growing Varroa population. The Varroa mite is therefore considered to be the largest contributor to winter losses.
The United States Department of Agriculture (USDA) has shown that it is possible to select honey bees with Varroa Sensitive Hygiene (VSH) behavior: these bees can detect reproducing Varroa in brood. As these VSH bees remove the infested brood, no Varroa offspring is produced. Selection has only been limited to this trait and no resources were available yet to structurally integrate this trait in a broader base of the honey bee population.
In the spring of 2014, the European team created more than one hundred small colonies, a quarter with a USDA-VSH background and the others with a European background. The queens were artificially inseminated with only one drone, instead of the approximate ten which are normally used, ensuring that all worker bees had not only the same mother, but also the same father, so that they inherit the same traits. The EU queens and drones were selected from colonies with lower amounts of Varroa and good hygienic behavior.
After an extra infestation with Varroa mites, the colonies were investigated at the end of the summer for the fraction of non-reproducing mites in the brood, this being the key measurement for establishing the level of VSH. In total more than 20 colonies were identified with high levels (more than 75%) of the VSH behavior. Half of these colonies are from the European background, so these results show that the VSH behavior, previously shown in the USDA research colonies, is also present in European bees. The results also show that VSH behavior can be brought to a high level in a short period of time using the Single Drone Insemination technique.
The next step in the breeding program, starting in the 2015 season, will be to further select towards 100% VSH in the EU breeding stock. Once this level is reached, normal sized, multi-drone colonies will be created and thoroughly tested on other important traits like honey production, gentleness and swarming tendency. Also the selection has to be done in as many different lines of honey bees as possible to ensure a rich biodiversity and to enable its broad application in the beekeeper community worldwide.
About the Arista Bee Research Foundation
The Arista Bee Research Foundation was established at the end of 2013 with the goal to breed healthier, Varroa resistant, honey bees. The foundation is a non-profit organization, scientifically supported by senior researchers from the United States Department of Agriculture (USDA, Baton Rouge), the Kirchhain Bee Institute (Germany), the Hohen Neuendorf Bee Institute (Germany) and the Wageningen University (The Netherlands). The Arista Bee Research foundation is looking for financial support to enable the continuation of this important work.