The ongoing debate about glyphosate-based herbicides (GBH) and their implications for beneficial arthropods gives rise to controversy. This research was carried out to cover possible sublethal GBH effects on the brood and colony development, adult survival, and overwintering success of honey bees (Apis mellifera L.) under field conditions. Residues in bee relevant matrices, such as nectar, pollen, and plants, were additionally measured. To address these questions, we adopted four independent study approaches. For brood effects and survival, we orally exposed mini-hives housed in the “Kieler mating-nuc” system to sublethal concentrations of 4.8 mg glyphosate/kg (T1, low) and 137.6 mg glyphosate/kg (T2, high) over a period of one brood cycle (21 days). Brood development and colony conditions were assessed after a modified OECD method (No. 75). For adult survival, we weighed and labeled freshly emerged workers from control and exposed colonies and introduced them into non-contaminated mini-hives to monitor their life span for 25 consecutive days. The results from these experiments showed a trivial effect of GBH on colony conditions and the survival of individual workers, even though the hatching weight was reduced in T2. The brood termination rate (BTR) in the T2 treatment, however, was more than doubled (49.84%) when compared to the control (22.11%) or T1 (20.69%). This was surprising as T2 colonies gained similar weight and similar numbers of bees per colony compared to the control, indicating an equal performance. Obviously, the brood development in T2 was not “terminated” as expected by the OECD method terminology, but rather “slowed down” for an unknown period of time. In light of these findings, we suggest that chronic high GBH exposure is capable of significantly delaying worker brood development, while no further detrimental effects seem to appear at the colony level. Against this background, we discuss additional results and possible consequences of GBH for honey bee health.

中文翻译：

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长期高草甘膦暴露会延缓田间条件下个体工蜂（Apis mellifera L.）的发育

关于草甘膦类除草剂（GBH）及其对有益节肢动物的影响的争论一直在引起争议。进行这项研究的目的是探讨可能的致死性GBH对蜜蜂的繁殖和集落发育，成年存活率以及越冬成功的影响（Apis melliferaL.）在野外条件下。还测量了蜜蜂相关基质（如花蜜，花粉和植物）中的残留物。为了解决这些问题，我们采用了四种独立的研究方法。为了提高繁殖力和存活率，我们在一段时间内对“基尔交配-nuc”系统中安置的微型细棚进行了口服致死性暴露，分别检测到亚致命浓度分别为4.8 mg草甘膦/ kg（T1，低）和137.6 mg草甘膦/ kg（T2，高）一个育雏周期（21天）。经改良的OECD方法（第75号）评估了雏鸡的发育和菌落状况。对于成年生存，我们称重并标记了来自对照和裸露的菌落的新出现的工人，并将它们引入未受污染的小型蜂箱中，以连续25天监控其寿命。这些实验的结果表明，即使在T2中孵化重量减少，GBH对菌落条件和个体工人的生存也没有什么影响。然而，与对照组（22.11％）或T1（20.69％）相比，T2处理的育雏终止率（BTR）增加了一倍以上（49.84％）。这是令人惊讶的，因为与对照相比，T2菌落的体重和每菌落的蜜蜂数量相似，表明性能相同。显然，T2阶段的育雏发展并未像经合组织方法术语所预期的那样“终止”，而是在未知的时间内“放慢了速度”。根据这些发现，我们建议慢性高GBH暴露能够显着延迟工人育雏的发展，而在菌落水平上似乎没有进一步的有害作用。