Centre for Functional Ecology, Department of Life Sciences, Associated Laboratory TERRA, University of Coimbra, Portugal.
Centre for Functional Ecology, Department of Life Sciences, Associated Laboratory TERRA, University of Coimbra, Portugal.
Sci Total Environ. 2022 Sep 1;837:155710. doi: 10.1016/j.scitotenv.2022.155710. Epub 2022 May 6.
Agricultural intensification has increased the number of stressors that pollinators are exposed to. Besides increasing landscape fragmentation that limit the supply of flower resources, intensive agricultural practices relying on the use of pesticides to control agricultural pests also affect non-target organisms like honey bees. The use of most pesticides containing neonicotinoids has been severely restricted in the European Union, leaving pesticides containing acetamiprid as the only ones that are still authorized. In the meantime, new substances like sulfoxaflor, that have a similar mode of action acting on the insect's nicotinic acetylcholine receptors (nAChR), have been approved for agricultural use. In Europe and USA, the use of pesticides containing this active ingredient is limited due to toxic effects already reported on bees, but no restrictions regarding this matter were applied in other countries (e.g., Brazil). In this study, homing ability tests with acetamiprid and sulfoxaflor were performed, in which honey bees were fed with three sub-lethal doses from each substance. After exposure, each honey bee was equipped with an RFID chip and released 1 km away from the colony to evaluate their homing ability. No significant effects were detected in honey bees fed with 32, 48 and 61 ng of acetamiprid while a poor performance on their homing ability, with only 28% of them reaching the colony instead of 75%, was detected at a 26 ng/a.s./bee dose of sulfoxaflor. Although, both pesticides act on the nAChR, the higher sulfoxaflor toxicity might be related with the honey bees detoxifying mechanisms, which are more effective on cyano-based neonicotinoids (i.e., acetamiprid) than sulfoximines. With this study we encourage the use of homing ability tests to be a suitable candidate to integrate the future risk assessment scheme, providing valuable data to models predicting effects on colony health that emerge from the individual actions of each bee.
农业集约化增加了传粉媒介所面临的压力源数量。除了增加限制花卉资源供应的景观破碎化外，依赖使用杀虫剂来控制农业害虫的集约化农业实践也会影响到非目标生物，如蜜蜂。在欧盟，大多数含有新烟碱类的杀虫剂的使用已受到严格限制，只剩下含有噻虫胺的杀虫剂仍被授权使用。与此同时，新的物质，如噻虫嗪，具有类似的作用模式，作用于昆虫的烟碱型乙酰胆碱受体（nAChR），已被批准用于农业用途。在欧洲和美国，由于已报道对蜜蜂有毒性作用，含有这种活性成分的杀虫剂的使用受到限制，但在其他国家（例如巴西）没有对此类物质施加限制。在这项研究中，进行了噻虫胺和噻虫嗪的归巢能力测试，在测试中，蜜蜂喂食了三种亚致死剂量的这两种物质。暴露后，每只蜜蜂都配备了一个 RFID 芯片，并在距离蜂巢 1 公里的地方释放，以评估它们的归巢能力。喂食 32、48 和 61ng 噻虫胺的蜜蜂没有表现出明显的影响，而喂食 26ng/a.s./bee 剂量的噻虫嗪的蜜蜂归巢能力较差，只有 28%的蜜蜂能够回到蜂巢，而不是 75%。尽管这两种杀虫剂都作用于 nAChR，但噻虫嗪毒性更高可能与蜜蜂的解毒机制有关，这种机制对基于氰基的新烟碱类（如噻虫胺）比噻虫嗪更有效。通过这项研究，我们鼓励使用归巢能力测试作为整合未来风险评估方案的合适候选方案，为预测个体蜜蜂行为对蜂群健康影响的模型提供有价值的数据。
