Bats are potentially exposed to pesticides via foraging in croplands. Common pesticides like organophosphates are neurotoxic for vertebrates and even low doses can impair essential processes such as locomotion and cognition. These sublethal effects are usually studied using molecular biomarkers with limited ecological relevance. Behavioral studies, in contrast, represent a more informative yet sensitive approach. Spatial navigation, for example, is an ecologically relevant behavior that is modulated by cellular pathways potentially targeted by neurotoxicants. We evaluated whether bats’ ability to memorize and navigate novel spaces was negatively affected by environmental relevant doses of chlorpyrifos, a common organophosphate insecticide. We also tested how the behavioral response correlated with molecular biomarkers. We orally dosed captive big brown bats (Eptesicus fuscus) with chlorpyrifos and studied exploratory behavior in two testing arenas. We evaluated similarity of stereotype flight trajectories in a flight tent, and associative memory in a Y-maze. We quantified brain cholinesterase (ChE) activity as a cellular biomarker and employed non-targeted proteomics as molecular biomarkers. Bats exposed to chlorpyrifos were less explorative and made more incorrect choices in the Y-maze, but the consistency of their flight trajectories was unaffected. Exposed bats had 30% lower ChE activity, showed down-regulation of proteins involved in memory (VP37D), learning and sound perception (NOX3). Other important nervous system processes such as synaptic function, plasticity, oxidative stress, and apoptosis were enriched in chlorpyrifos-exposed bats. These results support the sensitivity of behavior as a biomarker of toxicity and the importance of considering other levels of organization to help explain the mechanisms underlying altered behavior due to human activities.

中文翻译：

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常见杀虫剂以符合环境的剂量影响蝙蝠的空间导航

蝙蝠可能通过在农田觅食而接触到杀虫剂。常见的杀虫剂（如有机磷酸盐）对脊椎动物具有神经毒性，即使是低剂量也会损害运动和认知等基本过程。这些亚致死效应通常使用具有有限生态相关性的分子生物标志物进行研究。相比之下，行为研究代表了一种信息更丰富但更敏感的方法。例如，空间导航是一种生态相关的行为，它受到神经毒物可能靶向的细胞通路的调节。我们评估了蝙蝠记忆和导航新空间的能力是否受到环境相关剂量毒死蜱（一种常见的有机磷杀虫剂）的负面影响。我们还测试了行为反应如何与分子生物标志物相关联。蜉蝣) 与毒死蜱并在两个测试领域研究了探索行为。我们评估了飞行帐篷中刻板印象飞行轨迹的相似性，以及 Y 迷宫中的联想记忆。我们将脑胆碱酯酶 (ChE) 活性量化为细胞生物标志物，并采用非靶向蛋白质组学作为分子生物标志物。暴露于毒死蜱的蝙蝠探索性较差，在 Y 形迷宫中做出更多错误选择，但它们飞行轨迹的一致性不受影响。暴露的蝙蝠的 ChE 活性降低了 30%，显示出与记忆 (VP37D)、学习和声音感知 (NOX3) 有关的蛋白质的下调。其他重要的神经系统过程，如突触功能、可塑性、氧化应激和细胞凋亡，在毒死蜱暴露的蝙蝠中得到了丰富。