Bumblebees are important pollinators of agricultural crops and wildflowers, but many species are in decline. Neonicotinoid insecticides are the most commonly used insecticide globally and can have negative sublethal effects on bumblebee colony growth and reproduction. Individual bumblebees can visit hundreds to thousands of flowers a day to forage for their colony. As such, they are a model species for studying optimal foraging, and small impairments to an individual’s foraging decisions may have compounding effects on the colony’s nutritional intake. We exposed bumblebees (Bombus impatiens) to an acute, field-realistic dose of the neonicotinoid insecticide imidacloprid, before allowing them to forage on an artificial floral array. We found that neonicotinoid-exposed bumblebees made suboptimal foraging decisions, as they were more likely to visit flowers located further apart than control bees. This indicates that for a given flower patch, individual bees exposed to a neonicotinoid will likely use more energy and forage less efficiency than unexposed bees, although further studies that directly measure energetic cost are required to confirm this. Given the robust and growing body of evidence demonstrating negative sublethal effects of neonicotinoids on bees, sublethal assessments on non-Apis bees should be made mandatory within the regulatory process.

中文翻译：

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暴露于新烟碱类农药的大黄蜂做出次优的觅食决定

大黄蜂是农作物和野花的重要传粉者，但许多物种正在减少。新烟碱类杀虫剂是全球最常用的杀虫剂，可能对大黄蜂群落的生长和繁殖产生负面的亚致死影响。个别大黄蜂每天可以参观成百上千朵花来觅食。因此，它们是研究最佳觅食的模型物种，对个体觅食决定的微小损害可能会对群体的营养摄入产生复合影响。我们将大黄蜂 (Bombus impatiens) 暴露于急性、田间真实剂量的新烟碱类杀虫剂吡虫啉，然后让它们在人造花卉阵列上觅食。我们发现暴露于新烟碱类物质的大黄蜂做出了次优的觅食决定，因为它们比对照蜜蜂更有可能参观距离更远的花朵。这表明对于给定的花斑，暴露于新烟碱类物质的个体蜜蜂可能会比未暴露的蜜蜂使用更多的能量和较低的觅食效率，尽管需要进一步研究直接测量能量成本来证实这一点。鉴于越来越多的证据表明新烟碱类物质对蜜蜂有负面的亚致死影响，在监管过程中应强制对非蜜蜂进行亚致死评估。