Adding habitat within agricultural ecosystems is necessary to reverse declines in pollinator abundance and diversity. Understanding pesticide exposure to pollinator habitat near crop fields is necessary to support risk assessments. Neonicotinoids applied to maize and soybean seeds can be transported from crop fields to adjacent habitat through dust drift during planting and/or through overland runoff or subsurface flow following planting. Pollinators, especially bees (e.g. Apidae) and monarch butterflies (Danaus plexippus), could be exposed to neonicotinoids through ingestion of contaminated plant material (e.g. milkweed leaves). Neonicotinoids have been detected in pollinator-attractive habitats near crop fields; however, the magnitude and seasonal variation of the concentration of these insecticides has not been determined. We quantified concentrations of clothianidin, thiamethoxam, and imidacloprid in soil and forb leaf tissue, including milkweed (Asclepias spp.) located within reconstructed prairies (3–4 years post-establishment) within or adjacent to maize or soybean fields. Samples taken from April through August in 2017 and 2018 were analyzed with liquid chromatography-tandem mass spectrometry; 100% of soil, 80% of vegetation from blooming forbs, and 80% of milkweed leaf tissue samples had at least one neonicotinoid present above the method detection limit (0.07–0.9 ng g^-1). The maximum concentrations detected in 2017 or 2018 of clothianidin, thiamethoxam, and imidacloprid in milkweed leaf tissue samples were 6.6, 12.9, and 2.8 ng g^-1, respectively. These values are 10 to 130-fold lower than the chronic LC₁₀ values for monarch larvae, indicating it is unlikely that this route of neonicotinoid exposure will cause adverse effects to monarch larvae.

在农业生态系统内增加栖息地对于扭转传粉媒介丰度和多样性的下降是必要的。了解农药对农田附近传粉媒介栖息地的暴露对于支持风险评估是必要的。应用于玉米和大豆种子的新烟碱类物质可以通过种植期间的灰尘漂移和/或种植后的地表径流或地下流从作物田转移到邻近的栖息地。传粉者，尤其是蜜蜂（例如Apidae）和帝王蝶（Danaus plexippus）)，可能会通过摄入受污染的植物材料（例如马利筋叶）而暴露于新烟碱类物质。在农田附近对传粉媒介具有吸引力的栖息地中已检测到新烟碱类物质；然而，这些杀虫剂浓度的幅度和季节性变化尚未确定。我们量化了土壤和杂草叶组织中噻虫胺、噻虫嗪和吡虫啉的浓度，包括马利筋（Asclepiasspp.) 位于玉米或大豆田内或附近的重建大草原内（建立后 3-4 年）。2017 年和 2018 年 4 月至 8 月采集的样品进行了液相色谱-串联质谱分析；100% 的土壤、80% 的开花植物和 80% 的乳草叶组织样本中至少存在一种新烟碱类物质高于方法检测限 (0.07–0.9 ng g ^-1 )。2017 年或 2018 年在马利筋叶组织样本中检测到的噻虫胺、噻虫嗪和吡虫啉的最大浓度分别为 6.6、12.9 和 2.8 ng g ^-1。这些值比慢性 LC 低 10 到 130 倍₁₀ 君主幼虫的值，表明这种新烟碱暴露途径不太可能对君主幼虫造成不利影响。