Texas Tech University, Department of Environmental Toxicology, Lubbock, TX, 79409, United States.
Texas Tech University, Department of Environmental Toxicology, Lubbock, TX, 79409, United States.
Environ Pollut. 2021 Oct 1;286:117142. doi: 10.1016/j.envpol.2021.117142. Epub 2021 May 3.
Cavity nesting bees are proficient and important pollinators that can augment or replace honey bee pollination services for some crops. Relatively little is known about specific pesticide concentrations present in cavity nesting insect reed matrices and associated potential risks to cavity nesting bees. Nesting substrates (Phragmites australis reeds in bundles) were deployed in an agriculturally intensive landscape to evaluate colonization and agrochemical exposure among cavity nesting pollinators over two consecutive field seasons. Composition of insect species colonizing reeds within nest bundles varied considerably; those placed near beef cattle feed yards were dominated by wasps (93% of the total number of individuals occupying reed nest bundles), whereas nest bundles deployed in cropland-dominated landscapes were colonized primarily by leaf cutter bees (71%). All nesting/brood matrices in reeds (mud, leaves, brood, pollen) contained agrochemicals. Mud used in brood chamber construction at feed yard sites contained 21 of 23 agrochemicals included in analysis and >70% of leaf substrate stored in reeds contained at least one agrochemical. Moxidectin was most frequently detected across all reed matrices from feed yard sites, and moxidectin concentrations in nonviable larvae were more than four times higher than those quantified in viable larvae. Agrochemical concentrations in leaf material and pollen were also quantified at levels that may have induced toxic effects among developing larvae. To our knowledge, this is the first study to characterize agrochemical concentrations in multiple reed matrices provisioned by cavity-nesting insects. Use of nest bundles revealed that cavity nesting pollinators in agriculturally intensive regions are exposed to agrochemicals during all life stages, at relatively high frequencies, and at potentially lethal concentrations. These results demonstrate the utility of nest bundles for characterizing risks to cavity nesting insects inhabiting agriculturally intensive regions.
腔巢筑巢蜂是熟练且重要的传粉者，它们可以为一些作物补充或替代蜜蜂传粉服务。目前对于腔巢筑巢昆虫芦苇基质中存在的特定农药浓度以及对腔巢筑巢蜂的潜在风险了解甚少。将巢基质（成束的芦苇）部署在农业密集型景观中，以评估腔巢筑巢传粉者在两个连续的野外季节中的定殖和农用化学品暴露情况。在巢束内定殖的昆虫物种组成差异很大；那些放置在肉牛饲料场附近的巢束主要被黄蜂（占据芦苇巢束的个体总数的 93%）占据，而在以耕地为主的景观中部署的巢束则主要被叶切蜂（71%）占据。芦苇中的所有巢/育雏基质（泥、叶、育雏、花粉）都含有农用化学品。饲料场地点的育雏室建筑中使用的泥土含有分析中包含的 23 种农用化学品中的 21 种，储存在芦苇中的 70%以上的叶基质至少含有一种农用化学品。莫昔克丁在来自饲料场的所有芦苇基质中最常被检测到，且在非存活幼虫中的浓度比在存活幼虫中量化的浓度高四倍以上。还定量了叶材料和花粉中的农用化学品浓度，这些浓度可能在发育中的幼虫中引起了毒性作用。据我们所知，这是第一项描述腔巢筑巢昆虫提供的多种芦苇基质中农用化学品浓度的研究。使用巢束表明，在农业密集地区，腔巢筑巢传粉者在所有生命阶段都以相对较高的频率接触农用化学品，且浓度可能具有致命性。这些结果表明，巢束可用于描述栖息在农业密集地区的腔巢筑巢昆虫的风险。
