Exploring a treatment strategy for long-term increase of varroa tolerance on Marmara Island, Turkey

Abstract

We explored practical steps to implement a sustainable treatment against Varroa destructor which is adapted to common beekeeping situations, and applies conventional control but nevertheless exerts selection pressure towards increased mite tolerance in honey bees. This approach approximates conditions of natural selection in host-parasite systems, and is supported by evidence that the impact of V. destructor decreases when bee populations are overexploited by the parasites. However, instead of a "live or let die" approach to selection, which is not feasible for commercial beekeeping, death of highly infested colonies was mimicked by treatment and requeening. We established a feasible treatment threshold based on powder sugar shaking of worker bee samples in 250 colonies kept by four beekeepers on the island of Marmara, Turkey. We subsequently requeened heavily infested colonies with queens from lightly infested colonies using simple methods. We found that although one third of the colonies were routinely left untreated, it was possible to decrease mean mite infestation levels and maintain a stable bee population in our apiaries.