Insecticide exposure has been identified as a contributing stressor to the decline in the North American monarch butterfly Danaus plexippus L. (Lepidoptera: Nymphalidae) population. Monarch toxicity data are currently limited and available data focuses on lethal endpoints. This study examined the 72-h toxicity of two pyrethroid insecticides, bifenthrin and β-cyfluthrin, and their effects on growth and diet consumption. The toxicity of bifenthrin to caterpillars was lower than β-cyfluthrin after 72 h. Survival was the most sensitive endpoint for bifenthrin, but diet consumption and caterpillar growth were significantly reduced at sublethal levels of β-cyfluthrin. Using AgDRIFT spray drift assessment, the aerial application of bifenthrin or β-cyfluthrin is predicted to pose the greatest risk to fifth-instar caterpillars, with lethal insecticide deposition up to 28 m for bifenthrin and up to 23 m for β-cyfluthrin from treated edges of fields. Low boom ground applications are predicted to reduce distances of lethal insecticide exposure to 2 m from the treated field edge for bifenthrin and β-cyfluthrin. Growth and survival of fifth-instar monarch caterpillars developing within the margins of a treated field may be significantly impacted following foliar applications of bifenthrin or β-cyfluthrin. These findings provide evidence that pyrethroid insecticides commonly used for soybean pest control are a potential risk to monarch caterpillars in agricultural landscapes.

中文翻译：

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拟除虫菊酯暴露减少帝王蝶（鳞翅目：蛱蝶科）毛虫的生长和发育

杀虫剂暴露已被确定为导致北美帝王蝶 Danaus plexippus L.（鳞翅目：蛱蝶科）种群数量下降的压力源。君主毒性数据目前是有限的，可用数据集中在致命的终点。本研究检测了两种拟除虫菊酯杀虫剂联苯菊酯和 β-氟氯氰菊酯的 72 小时毒性，以及它们对生长和饮食消耗的影响。72 h后联苯菊酯对毛虫的毒性低于β-氟氯氰菊酯。生存是联苯菊酯最敏感的终点，但在 β-氟氯氰菊酯的亚致死水平下，饮食消耗和毛虫生长显着降低。使用 AgDRIFT 喷雾漂移评估，联苯菊酯或 β-氟氯氰菊酯的空中施用预计对五龄毛虫构成最大风险，在处理过的田地边缘，联苯菊酯的致死性杀虫剂沉积高达 28 m，β-氟氯氰菊酯高达 23 m。对于联苯菊酯和 β-氟氯氰菊酯，低喷杆地面应用预计可将致死杀虫剂暴露距离减少至距处理过的田间边缘 2 m。叶面施用联苯菊酯或 β-氟氯氰菊酯后，在处理过的田地边缘发育的五龄帝王毛虫的生长和存活可能会受到显着影响。这些发现提供了证据，证明常用于大豆害虫控制的拟除虫菊酯杀虫剂对农业景观中的帝王毛虫具有潜在风险。对于联苯菊酯和 β-氟氯氰菊酯，低喷杆地面应用预计可将致死杀虫剂暴露距离减少至距处理过的田间边缘 2 m。叶面施用联苯菊酯或 β-氟氯氰菊酯后，在处理过的田地边缘发育的五龄帝王毛虫的生长和存活可能会受到显着影响。这些发现提供了证据，证明常用于大豆害虫控制的拟除虫菊酯杀虫剂对农业景观中的帝王毛虫具有潜在风险。对于联苯菊酯和 β-氟氯氰菊酯，低喷杆地面应用预计可将致死杀虫剂暴露距离减少至距处理过的田间边缘 2 m。叶面施用联苯菊酯或 β-氟氯氰菊酯后，在处理过的田地边缘发育的五龄帝王毛虫的生长和存活可能会受到显着影响。这些发现提供了证据，证明常用于大豆害虫控制的拟除虫菊酯杀虫剂对农业景观中的帝王毛虫具有潜在风险。