Bahreini Rassol, González-Cabrera Joel, Hernández-Rodríguez Carmen Sara, Moreno-Martí Sara, Muirhead Samantha, Labuschagne Renata B, Rueppell Olav
Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
Institute BIOTECMED, Universitat de València, Valencia, Spain.
Sci Rep. 2025 Jan 10;15(1):1587. doi: 10.1038/s41598-025-85279-6.
The ectoparasitic mite Varroa destructor remains a great threat for the beekeeping industry, for example contributing to excessive winter colony loss in Canada. For decades, beekeepers have sequentially used the registered synthetic varroacides tau-fluvalinate, coumaphos, amitraz, and flumethrin, leading to the risk of resistance evolution in the mites. In addition to the widespread resistance to coumaphos and pyrethroids, a decline in amitraz efficacy has recently been reported in numerous beekeeping regions in Canada. The goals of this study were to assess the evolution of resistance to amitraz in Canadian mite populations and to evaluate the presence and incidence of mutations previously associated with resistance to amitraz and pyrethroids in V. destructor. Our bioassay results confirmed the presence of amitraz-resistant mites in the population of Alberta. These phenotypic results were complemented by targeted genotyping of the octopamine receptor gene OctβR which revealed the presence of the mutation Y215H in 90% of tested apiaries with local allele frequencies ranging from 5 to 95%. The phenotypic resistance showed a significant correlation with the presence of this mutation across apiaries. In parallel, the L925I and L925M mutations in the voltage-gated sodium channel were identified in 100% of the tested apiaries with frequencies ranging from 33 to 97%, suggesting that resistance to pyrethroids remains widespread. These results support the notion that the practice of relying on a single treatment for a prolonged period can increase rates of resistance to current varroacides. Our findings suggest the need for large-scale resistance monitoring via genotyping to provide timely information to beekeepers and regulators. This will enable them to make an effective management plan, including rotation of available treatments to suppress or at least delay the evolution of resistance in V. destructor populations.
外寄生螨类瓦螨（Varroa destructor）仍然是养蜂业面临的重大威胁，例如在加拿大，它会导致冬季蜂群大量损失。几十年来，养蜂人依次使用已注册的合成杀螨剂氟氯苯菊酯、蝇毒磷、双甲脒和氟氯氰菊酯，这导致螨类产生抗药性进化的风险。除了对蝇毒磷和拟除虫菊酯普遍产生抗性外，最近在加拿大的许多养蜂地区还报告了双甲脒功效的下降。本研究的目的是评估加拿大螨类种群对双甲脒抗性的进化情况，并评估先前与瓦螨对双甲脒和拟除虫菊酯抗性相关的突变的存在情况和发生率。我们的生物测定结果证实，艾伯塔省的螨类种群中存在对双甲脒具有抗性的螨。这些表型结果通过对章鱼胺受体基因OctβR的靶向基因分型得到补充，该基因分型显示，在90%的测试蜂场中存在Y215H突变，当地等位基因频率范围为5%至95%。表型抗性与各蜂场中该突变的存在呈显著相关性。同时，在100%的测试蜂场中都鉴定出了电压门控钠通道中的L925I和L925M突变，频率范围为33%至97%，这表明对拟除虫菊酯的抗性仍然普遍存在。这些结果支持了长期依赖单一处理方法会增加对当前杀螨剂抗药性发生率的观点。我们的研究结果表明，需要通过基因分型进行大规模抗性监测，以便及时向养蜂人和监管机构提供信息。这将使他们能够制定有效的管理计划，包括轮换使用现有处理方法，以抑制或至少延缓瓦螨种群抗药性的进化。
