Insect biomass is declining across the globe at an alarming rate. Climate change and the widespread use of pesticides have been hypothesized as two underlying drivers. However, the lack of systematic experimental studies across chemicals and species limits our causal understanding of this problem. Here, we employed a chemical library encompassing 1024 different molecules (including insecticides, herbicides, fungicides, and plant growth inhibitors) to investigate how insect populations are affected by varying concentrations of pesticides, focusing on sublethal doses. Using a controlled laboratory pipeline for Drosophila melanogaster, we found that 57% of these chemicals affect the behavior of larvae at sublethal concentrations, and an even higher proportion compromises long-term survivability after acute exposure. Consistent with these results, we observed that exposure to chemicals at doses orders of magnitude below lethality induced widespread phosphorylation changes across the larval proteome. The effects of agrochemicals were amplified when the ambient temperature was increased by four degrees. We also tested the synergistic effects of multiple chemicals at doses found widely in nature and observed fitness-reducing changes in larval developmental time, behavior, and reproduction. Finally, we expanded our investigation to additional fly species, mosquitos, and butterflies and detected similar behavioral alterations triggered by pesticides at sublethal concentrations. Our results provide experimental evidence that strongly suggests sublethal doses of agrochemicals coupled with changes in environmental temperatures are contributing to the global decline in insect populations. We anticipate that our assays can contribute to improving chemical safety assessment, better protect the environment, secure food supplies, and safeguard animal and human health, as well as understand our rapidly changing world.

中文翻译：

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农用化学品普遍存在的亚致死效应是导致昆虫数量减少的因素

全球昆虫生物量正在以惊人的速度下降。气候变化和农药的广泛使用被认为是两个潜在的驱动因素。然而，缺乏跨化学物质和物种的系统实验研究限制了我们对这个问题的因果理解。在这里，我们使用了包含 1024 种不同分子（包括杀虫剂、除草剂、杀菌剂和植物生长抑制剂）的化学库来研究昆虫种群如何受到不同浓度农药的影响，重点关注亚致死剂量。使用针对果蝇的受控实验室管道，我们发现这些化学物质中有 57% 在亚致死浓度下会影响幼虫的行为，甚至更高的比例会影响急性暴露后的长期生存能力。与这些结果一致，我们观察到，暴露于低于致死率几个数量级的化学物质会引起幼虫蛋白质组的广泛磷酸化变化。当环境温度升高四度时，农用化学品的作用就会放大。我们还测试了自然界中广泛存在的多种化学物质的协同效应，并观察了幼虫发育时间、行为和繁殖的适应性降低变化。最后，我们将调查范围扩大到其他苍蝇物种、蚊子和蝴蝶，并检测到亚致死浓度的农药引发的类似行为改变。我们的研究结果提供了实验证据，强烈表明亚致死剂量的农用化学品加上环境温度的变化正在导致全球昆虫数量的下降。我们预计我们的检测可以有助于改善化学品安全评估，更好地保护环境，确保食品供应，保障动物和人类健康，并了解我们快速变化的世界。