Department of Integrative Biology, University of Texas at Austin, TX, USA.
Sci Total Environ. 2023 May 10;872:162102. doi: 10.1016/j.scitotenv.2023.162102. Epub 2023 Feb 9.
The widespread use of glyphosate-based formulations to eliminate unwanted vegetation has increased concerns regarding their effects on non-target organisms, such as honey bees and their gut microbial communities. These effects have been associated with both glyphosate and co-formulants, but it is still unknown whether they translate to other bee species. In this study, we tested whether glyphosate, pure or in herbicide formulation, can affect the gut microbiota and survival rates of the eastern bumble bee, Bombus impatiens. We performed mark-recapture experiments with bumble bee workers from four different commercial colonies, which were exposed to field relevant concentrations of glyphosate or a glyphosate-based formulation (0.01 mM to 1 mM). After a 5-day period of exposure, we returned the bees to their original colonies, and they were sampled at days 0, 3 and 7 post-exposure to investigate changes in microbial community and microbiota resilience by 16S rRNA amplicon sequencing and quantitative PCR. We found that exposure to glyphosate, pure or in herbicide formulation, reduced the relative abundance of a beneficial bee gut bacterium, Snodgrassella, in bees from two of four colonies when compared to control bees at day 0 post-exposure, but this reduction became non-significant at days 3 and 7 post-exposure, suggesting microbiota resilience. We did not find significant changes in total bacteria between control and exposed bees. Moreover, we observed an overall trend in decreased survival rates in bumble bees exposed to 1 mM herbicide formulation during the 7-day post-exposure period, suggesting a potential negative effect of this formulation on bumble bees.
草甘膦制剂的广泛使用来消除不需要的植被，增加了人们对其对非目标生物，如蜜蜂及其肠道微生物群落的影响的担忧。这些影响与草甘膦和共溶剂都有关，但仍不清楚它们是否会转化为其他蜜蜂物种。在这项研究中，我们测试了草甘膦，无论是纯的还是在除草剂配方中，是否会影响东部大黄蜂（Bombus impatiens）的肠道微生物群和生存率。我们用来自四个不同商业蜂群的大黄蜂工蜂进行了标记-重捕实验，这些蜂群暴露在与田间相关的草甘膦或草甘膦制剂浓度下（0.01 mM 至 1 mM）。暴露 5 天后，我们将蜜蜂送回原来的蜂群，并在暴露后第 0、3 和 7 天对它们进行采样，通过 16S rRNA 扩增子测序和定量 PCR 来研究微生物群落和微生物群弹性的变化。我们发现，与对照蜜蜂相比，暴露于草甘膦纯品或除草剂配方中，在暴露后第 0 天，四个蜂群中的两个蜂群的蜜蜂肠道有益细菌 Snodgrassella 的相对丰度降低，但在暴露后第 3 和 7 天，这种减少变得不显著，表明微生物群具有弹性。我们没有发现对照和暴露的蜜蜂之间总细菌数量有显著变化。此外，我们观察到在暴露于 1 mM 除草剂配方后的 7 天内，大黄蜂的存活率总体呈下降趋势，这表明这种配方对大黄蜂可能有潜在的负面影响。
