Abstract Insecticidal neonicotinoid seed treatments are a common agricultural insect pest management strategy; however, effects on nontarget pests and omnivorous arthropods are understudied. We used a series of experiments to evaluate impacts of the neonicotinoid seed treatment thiamethoxam on densities of herbivorous twospotted spider mites (Tetranychus urticae Koch [Acari:Tetranychidae]) and feeding behavior of western flower thrips (Frankliniella occidentalis Pergande [Thysanoptera: Thripidae]), an omnivore that feeds on spider mite eggs but is also a significant plant pest. Spider mite densities were higher on neonicotinoid-treated soybeans, but only when mites were not spatially confined.We then examined how availability of thiamethoxam-treated food items (i.e., eggs from spider mites reared on treated soybeans, soybean leaf discs, or a combination of the two), and previous exposure to thiamethoxam-treated soybean impacted thrips feeding. Regardless of the presence of leaf tissue, thrips consumed fewer spider mite eggs laid by females reared on treated soybeans, suggesting spider mite eggs can serve as poisoned prey. Overall, thrips consumed less treated soybean leaf tissue, and thrips on treated leaf discs had a lower percentage of herbivorous feeding events and consumed more nontreated spider mite eggs, indicating a dietary shift from herbivory to predation. The neonicotinoid status of spider mite eggs and prior exposure of thrips also caused shifts in the number and size of leaf scars, likely as a result of altered foraging behavior and/or movement. Shifts between herbivory and predation have implications for thrips damage, virus transmission, and pest management, especially in systems with mixtures of nontreated and neonicotinoid-treated plants.

中文翻译：

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新烟碱类种子处理对大豆非目标食草动物（双斑叶螨）的影响和共生杂食动物（西花蓟马）的饮食转换

摘要 杀虫新烟碱种子处理是一种常见的农业害虫防治策略；然而，对非目标害虫和杂食性节肢动物的影响尚未得到充分研究。我们使用一系列实验来评估新烟碱类种子处理噻虫嗪对草食性双斑叶螨（Tetranychus urticae Koch [Acari:Tetranychidae]）的密度和西部花蓟马（Frankliniella occidentalis Pergande）的摄食行为的影响：[Thripidae]一种以蜘蛛螨卵为食的杂食动物，也是一种重要的植物害虫。新烟碱处理过的大豆上的叶螨密度较高，但仅当螨虫不受空间限制时。然后我们检查了噻虫嗪处理过的食物（即，在处理过的大豆上饲养的叶螨卵、大豆叶盘、或两者的组合），并且之前接触过噻虫嗪处理的大豆影响了蓟马的摄食。不管叶组织是否存在，蓟马消耗的叶螨卵由用处理过的大豆饲养的雌性所产，这表明叶螨卵可以作为有毒的猎物。总体而言，蓟马消耗较少的处理过的大豆叶组织，处理过的叶盘上的蓟马具有较低的食草性摄食事件百分比，并消耗了更多未经处理的叶螨卵，表明饮食从食草转向捕食。叶螨卵的新烟碱状态和蓟马的先前暴露也导致叶痕数量和大小的变化，这可能是觅食行为和/或运动改变的结果。食草和捕食之间的转变对蓟马的损害、病毒传播和害虫管理有影响，