General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany; Zoology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt.
Department of Community Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, 06120 Halle (Saale), Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstrasse 4, 04103 Leipzig, Germany; Institute of Biology/Geobotany and Botanical Garden, Martin Luther University Halle-Wittenberg, Am Kirchtor 1, 06108 Halle (Saale), Germany.
Sci Total Environ. 2022 Nov 25;849:157941. doi: 10.1016/j.scitotenv.2022.157941. Epub 2022 Aug 9.
The gut microbiome plays an important role in bee health and disease. But it can be disrupted by pesticides and in-hive chemicals, putting honey bee health in danger. We used a controlled and fully crossed laboratory experimental design to test the effects of a 10-day period of chronic exposure to field-realistic sublethal concentrations of two nicotinic acetylcholine receptor agonist insecticides (nACHRs), namely flupyradifurone (FPF) and sulfoxaflor (Sulf), and a fungicide, azoxystrobin (Azoxy), individually and in combination, on the survival of individual honey bee workers and the composition of their gut microbiota (fungal and bacterial diversity). Metabarcoding was used to examine the gut microbiota on days 0, 5, and 10 of pesticide exposure to determine how the microbial response varies over time; to do so, the fungal ITS2 fragment and the V4 region of the bacterial 16S rRNA were targeted. We found that FPF has a negative impact on honey bee survival, but interactive (additive or synergistic) effects between either insecticide and the fungicide on honey bee survival were not statistically significant. Pesticide treatments significantly impacted the microbial community composition. The fungicide Azoxy substantially reduced the Shannon diversity of fungi after chronic exposure for 10 days. The relative abundance of the top 10 genera of the bee gut microbiota was also differentially affected by the fungicide, insecticides, and fungicide-insecticide combinations. Gut microbiota dysbiosis was associated with an increase in the relative abundance of opportunistic pathogens such as Serratia spp. (e.g. S. marcescens), which can have devastating consequences for host health such as increased susceptibility to infection and reduced lifespan. Our findings raise concerns about the long-term impact of novel nACHR insecticides, particularly FPF, on pollinator health and recommend a novel methodology for a refined risk assessment that includes the potential effects of agrochemicals on the gut microbiome of bees.
肠道微生物群在蜜蜂健康和疾病中起着重要作用。但它会被杀虫剂和蜂箱内的化学物质破坏，使蜜蜂的健康处于危险之中。我们使用了一种控制和完全交叉的实验室实验设计，来测试慢性暴露于田间实际亚致死浓度的两种烟碱型乙酰胆碱受体激动剂杀虫剂（nACHRs），即 flupyradifurone（FPF）和噻虫啉（Sulf），以及一种杀菌剂，唑菌胺酯（Azoxy），单独和组合，对单个蜜蜂工蜂的生存和它们肠道微生物群（真菌和细菌多样性）组成的影响。我们使用代谢组学在接触农药的第 0、5 和 10 天检查肠道微生物群，以确定微生物反应随时间的变化；为此，靶向了真菌 ITS2 片段和细菌 16S rRNA 的 V4 区。我们发现 FPF 对蜜蜂的生存有负面影响，但杀虫剂和杀菌剂之间的相互作用（相加或协同）对蜜蜂的生存没有统计学意义。农药处理显著影响了微生物群落的组成。杀菌剂 Azoxy 在慢性暴露 10 天后显著降低了真菌的 Shannon 多样性。蜜蜂肠道微生物群的前 10 个属的相对丰度也受到杀菌剂、杀虫剂和杀菌剂-杀虫剂组合的不同影响。肠道微生物群失调与机会性病原体（如沙雷氏菌属）相对丰度的增加有关，这可能对宿主健康产生破坏性后果，例如增加感染易感性和降低寿命。我们的研究结果引起了对新型 nACHR 杀虫剂（特别是 FPF）对传粉媒介健康的长期影响的关注，并建议采用一种新的方法来进行精细的风险评估，包括农用化学品对蜜蜂肠道微生物群的潜在影响。
