Insecticide use remains both ubiquitous and controversial around the world, due to its importance despite acknowledged inherent environmental risk. Neonicotinoid insecticides have been targeted as potential culprits of reported pollinator declines and decreases in insect abundance and diversity. Having systemic activity in plants, neonicotinoids can be used as seed treatments. Such use, associated with a relatively higher water solubility and soil persistence, may enhance the potential of these compounds to change the structure and function of food webs associated with crop plants. We therefore conducted a food web analysis to assess the short-term impact of seed treatments with the neonicotinoid imidacloprid on the arthropod community associated with Neotropical soybean fields. Imidacloprid-treated and untreated soybeans were cultivated for two seasons, and associated arthropods were sampled throughout the plant phenological cycle. The data collected were used to build plant–consumer–predator networks using food web analysis. We found that imidacloprid seed treatments significantly affected arthropod species richness and abundance in a preliminary analysis, thus affecting soybean-associated arthropod assemblage. However, this effect was secondary to cultivation season, unlike the findings from food web analysis where the effect of imidacloprid seed treatment prevailed. The effect of imidacloprid was significant especially on prey–predator asymmetries and proportion of taxa at higher trophic levels. Higher food web complexity was associated with imidacloprid-treated fields particularly during the 2nd cultivation season, but without impacting soybean yield. Our results suggest that imidacloprid soybean seed treatments impact the arthropod community within the crop, but do not necessarily reduce community complexity and have no noticeable effect on pest species and crop yield.

尽管承认存在固有的环境风险，但由于其重要性，杀虫剂的使用在世界范围内仍然普遍存在且存在争议。新烟碱类杀虫剂已成为报道传粉媒介减少和昆虫丰度和多样性下降的潜在罪魁祸首。在植物中具有系统活性的新烟碱类可用作种子处理剂。这种使用与相对较高的水溶性和土壤持久性相关，可能会增强这些化合物改变与农作物相关的食物网结构和功能的潜力。因此，我们进行了食物网分析，以评估用新烟碱类吡虫啉处理种子对与新热带大豆田相关的节肢动物群落的短期影响。用吡虫啉处理和未处理的大豆种植了两个季节，并在整个植物物候周期中对相关的节肢动物进行了取样。收集的数据用于使用食物网分析建立植物-消费者-捕食者网络。我们在初步分析中发现吡虫啉种子处理显着影响节肢动物物种的丰富度和丰度，从而影响大豆相关的节肢动物组合。然而，这种效应继发于种植季节，与食物网分析的结果不同，吡虫啉种子处理的效应占主导地位。吡虫啉的作用显着，特别是对捕食者的不对称性和较高营养水平的分类群比例。较高的食物网复杂性与吡虫啉处理的田地有关，特别是在第二个种植季节，但不影响大豆产量。我们的研究结果表明，吡虫啉大豆种子处理会影响作物内的节肢动物群落，但不一定会降低群落复杂性，对害虫种类和作物产量没有明显影响。