São Paulo State University (UNESP), Institute of Biosciences, Rio Claro, Brazil; Federal University of São Carlos, Department of Environmental Sciences, Sorocaba, Brazil.
Federal University of São Carlos, Department of Environmental Sciences, Sorocaba, Brazil.
Chemosphere. 2024 Sep;364:143254. doi: 10.1016/j.chemosphere.2024.143254. Epub 2024 Sep 2.
Pesticide use is a major factor contributing to the global decline in bee populations. Sublethal effects, such as behavior alterations, are neglected in pesticide regulation for pollinators. However, these effects can bring important information to understanding the impacts of pesticides on bees' daily activities. In this study, we aimed to investigate the effects of the insecticide acetamiprid (7 ng/μL) and the fungicide azoxystrobin (10 ng/μL) on the behavior of the Neotropical solitary bee Centris analis. Female and male bees were exposed to these chemicals continuously for 48 h, followed by an additional 48 h without contaminated food, totaling 96 h of observation. We used five experimental groups: control, solvent control, insecticide, fungicide, and pesticide mixture (insecticide + fungicide). Behavioral alterations based on locomotion and light response were assessed by video tracking at 48 (end of pesticide exposure) and 96 h (end of bioassay). In addition, after recording bees at 96 h, the individuals were anesthetized for brain collection and histological evaluation of mushroom bodies to evaluate if pesticides can damage their neurons and impair the cognitive processes and responses of bees to sensory stimuli. Bees exposed to acetamiprid and pesticide mixture showed lethargic movements and impaired locomotion at 48 h. Notably, these behavioral effects were no longer evident after the bees consumed uncontaminated food for an additional 48 h, totaling 96 h from the start of pesticide exposure. Only fungicide exposure did not result in any behavioral or brain histological changes. Therefore, our study showed that acetamiprid at an estimated residual concentration, despite being classified as having low toxicity for bees, can cause significant initial locomotion disruption in solitary bees. These findings highlight the importance of considering sublethal effects in environmental risk assessment.
农药的使用是导致全球蜜蜂数量减少的一个主要因素。对于传粉媒介来说，亚致死效应，如行为改变，在农药监管中被忽视了。然而，这些效应可以为理解农药对蜜蜂日常活动的影响提供重要信息。在这项研究中，我们旨在研究杀虫剂噻虫胺（7ng/μL）和杀菌剂唑菌酯（10ng/μL）对新热带独居蜂 Centris analis 行为的影响。雌性和雄性蜜蜂连续接触这些化学物质 48 小时，然后再接触 48 小时没有污染的食物，总共观察 96 小时。我们使用了五个实验组：对照组、溶剂对照组、杀虫剂组、杀菌剂组和农药混合物组（杀虫剂+杀菌剂）。通过视频跟踪，在 48 小时（农药暴露结束时）和 96 小时（生物测定结束时）评估基于运动和光反应的行为变化。此外，在记录蜜蜂 96 小时后，将个体麻醉以收集大脑并对蘑菇体进行组织学评估，以评估农药是否会损害它们的神经元，并损害蜜蜂对感觉刺激的认知过程和反应。在 48 小时时，接触噻虫胺和农药混合物的蜜蜂表现出呆滞的运动和运动障碍。值得注意的是，在蜜蜂再食用 48 小时无污染食物后，这些行为效应不再明显，从农药暴露开始总共 96 小时。只有接触杀菌剂没有导致任何行为或大脑组织学变化。因此，我们的研究表明，尽管噻虫胺被归类为对蜜蜂具有低毒性，但在估计的残留浓度下仍可能导致独居蜜蜂的初始运动障碍。这些发现强调了在环境风险评估中考虑亚致死效应的重要性。
