Council for Agricultural Research and Economics, Research Center for Agriculture and Environment (CREA-AA), Via di Corticella 133, 40128 Bologna, Italy.
Benef Microbes. 2020 Nov 15;11(7):641-654. doi: 10.3920/BM2019.0164. Epub 2020 Oct 30.
The honey bee parasitic mite is one of the main causes of depopulation of bee colonies. Bacterial symbionts associated to honey bees are known to produce a variety of bioactive molecules that have been suggested to play a protective role against honey bee pathogens. We hypothesised that among these bacteria, those colonising the external body of honey bees, and therefore able to survive and reproduce in the hive environment outside the insect gut, may be good candidate biocontrol agents to be tested against . The aim of this study was to isolate bacterial species from healthy honey bees and dead varroa mites and to evaluate the potential miticidal effect of their spent medium containing both bacterial metabolites and viable cells, with the final objective of finding a long-lasting solution for mite control. 61 bacterial strains belonging to the , and phyla were isolated from the surface of foragers, nurse bees and larvae collected in 10 different apiaries. The most common species was (62%). Growth capability of a selection of isolates was observed at 30 and 34 °C with 1% and 20% glucose and fructose. Laboratory bioassays were conducted by spraying mites with six-day-grown bacterial cultures containing 10 cfu/ml of four strains of and an bacterium. The effect of each strain on varroa survival was tested independently. The first three caused 95-100% mortality of mites in 3 days, indicating a potential role as natural antagonists towards varroa. The mediation of pH of the bacterial cultures did not appear to be determinant in mite inhibition, suggesting the involvement of other modes of action against varroa. The exploitation of honey bee microbiota for controlling one of the major threats for honey bee health may be a promising approach deserving further investigation.
蜜蜂寄生螨是导致蜂群衰落的主要原因之一。与蜜蜂共生的细菌被认为会产生多种生物活性分子，这些分子被认为对蜜蜂病原体起到了保护作用。我们假设，在这些细菌中，那些定植于蜜蜂外部身体的细菌，因此能够在蜂巢环境中生存和繁殖，而无需经过昆虫肠道，可能是对抗的潜在生物防治剂的良好候选物。本研究的目的是从健康的蜜蜂和死亡的瓦螨中分离细菌，并评估其含细菌代谢物和活菌的废弃培养基的潜在杀螨效果，最终目标是找到一种持久的螨虫控制解决方案。从 10 个不同的蜂场收集的采集蜂、护理蜂和幼虫的表面分离出了 61 株属于 、 和 门的细菌菌株。最常见的物种是 （62%）。在 30 和 34°C 下，用 1%和 20%葡萄糖和果糖观察到选择的分离株的生长能力。通过用含有 10 cfu/ml 的四种 和一种 细菌的六天培养物喷洒螨虫进行实验室生物测定。独立测试了每种菌株对瓦螨存活的影响。前三种菌株在 3 天内导致螨虫死亡率达到 95-100%，表明它们对瓦螨具有潜在的自然拮抗作用。细菌培养物的 pH 值调节似乎不是抑制螨虫的决定因素，这表明可能存在针对瓦螨的其他作用模式。利用蜜蜂微生物群来控制蜜蜂健康的主要威胁之一可能是一种有前途的方法，值得进一步研究。
