An investigation into the synergistic impact of sublethal exposure to industrial chemicals on the learning capacity and performance of bees

提高效率的持续压力推动了大型作物单一栽培的推广，这反过来又增加了作物遭受虫害的风险，并降低了自然授粉者和捕食者的密度和多样性。因此，我们发现自己严重依赖杀虫剂来保护脆弱的作物和蜜蜂来为它们授粉。全世界的蜜蜂种群正处于危机之中，大黄蜂的物种和种群正在下降。对蜜蜂来说，已确定的威胁包括气候条件的变化和各种螨虫和疾病的袭击。暴露于我们赖以保护农作物的各种农药混合物中也可能伤害有益的传粉者。具有讽刺意味的是，用来保护蜜蜂免受螨虫侵害的杀螨剂也可能对蜜蜂有害。所有动物的神经系统都是通过大脑中脑细胞（神经元）之间的快速信息传输来运作的。神经元使用化学信使（例如乙酰胆碱，ACh）进行通信，相邻的神经元使用特定的受体（例如ACh受体，AChR）对其做出反应。为了确保消息只被接收一次，过量的ACh被迅速灭活。接收神经元将这些信息传递给下一个神经元，因此信息在大脑中迅速传播。这种“兴奋性”的大脑活动被相反的（抑制性）活动所缓和，因此一些神经元没有反应。平衡这两个相反的信号提供了控制，并限制了大脑中危险的多动症。许多杀虫剂通过干扰昆虫大脑中的信息流而起作用。一些增加ACh释放，或抑制其去除，而另一些直接刺激AChRs或通过阻断抑制来去除制动。集体和亚毒性水平，农药可能会共同作用，改变大脑活动，如两种杀螨剂; Checkmite和Apistan。在低水平下，杀虫剂可能会引发过度活跃，引发癫痫发作，情绪障碍或学习和记忆改变。人们对这些亚毒性效应知之甚少，农药之间协同增效的潜力也基本上不为人知。我们假设，蜜蜂长期暴露于杀螨剂与亚毒性农药相结合，干扰关键的蜜蜂行为，如觅食，导航和通信。了解农药对行为的潜在协同作用所涉及的分子机制，需要一个简化的，但强大的模型。为了实现这一目标，我们将直接对从蜜蜂大脑中纯化并在实验室中培养的神经元进行研究。这些培养物将用于分析神经元对农药的反应，包括单独和组合。为了更长期和广泛的实用性（筛选和监测），我们建议开发新的蜜蜂细胞系。将使用脑切片监测脑电活动来验证神经元筛选方法的结果。使用这些技术，我们可以研究学习和记忆的分子基础，以及农药暴露如何影响学习和记忆。为了探索亚毒性暴露对蜜蜂和大黄蜂健康的影响，我们将调查它们执行学习任务的能力。我们还将使用一系列技术评估它们的导航、觅食和交流技能，包括对单个蜜蜂进行射频识别标记和解码蜜蜂摇摆舞。此外，我们将与苏格兰养蜂人协会（SBA）合作，对环境化学品对蜂群性能的影响进行为期3年的调查。SBA成员还将支持我们收集有关蜜蜂觅食的数据。该项目是一个独特的机会，可以建立一个具有互补技能和共同目标的英国科学家网络，以解决昆虫传粉媒介损失的问题。

The continual pressure for increased efficiency that has driven the spread of large crop monocultures has in turn increased the risk of pest damage to crops and driven down the density and diversity of natural pollinators and predators. As a result, we find ourselves critically dependent upon pesticides to protect vulnerable crops and the bees to pollinate them. Honeybee populations worldwide are in crisis and bumblebees species and populations are in decline. For honeybees, identified threats include changing climatic conditions and attack by various mites and diseases. Exposure to the varied cocktail of pesticides upon which we rely to protect crops could also be harming beneficial pollinators. Ironically, the miticides used to protect honeybees from mites may also be harmful to bees. The nervous system of all animals operates by the rapid transmission of information between brain cells (neurons) across the brain. Neurons communicate using chemical messengers (e.g. acetylcholine, ACh), to which a neighbouring neuron responds using specific receptors (e.g. ACh receptors, AChRs). To ensure that the message is received only once, excess ACh is rapidly inactivated. The recipient neuron passes this information on to the next neuron and so information spreads rapidly across the brain. This 'excitatory' brain activity is tempered by opposing (inhibitory) activity, whereby some neurons do not respond. Balancing these two opposing signals provides control and limits dangerous hyperactivity in the brain. Many pesticides act by interfering with information flow in the insect brain. Some increase ACh release, or inhibit its removal, while others directly stimulate AChRs or remove the brake by blocking the inhibition. Collectively and at sub-toxic levels, pesticides may act together to alter brain activity as seen for two miticides; Checkmite and Apistan. At low levels, pesticides might trigger hyperactivity to initiate epileptic seizures, mood disorders or altered learning and memory. These sub-toxic effects are poorly understood and the potential for synergy between pesticides is largely unknown. We hypothesise that the chronic exposure of honeybees to miticides combines with sub-toxic agricultural pesticides to disturb critical bee behaviours such as foraging, navigation and communication. Understanding the molecular mechanisms involved in potential synergistic actions of pesticides on behaviour requires a simplified, yet robust, model. To achieve this, we will perform studies directly on neurons purified from bee brains and cultured in the laboratory. These cultures will be used to analyse neuronal responses to pesticides, both alone and in combination. For more long-term and widespread utility (screening and monitoring), we propose to develop novel honeybee cell lines. Results from the neuronal screening approach will be validated using brain slices to monitor electrical brain activity. Using these techniques, we can study the molecular basis of learning and memory and how this is affected by pesticide exposure. To explore the consequences of combined sub-toxic exposures on honeybee and bumblebee health we will investigate their ability to perform learning tasks. We will also assess their navigation, foraging and communication skills using a range of techniques including radio frequency identification tagging of individual bees and decoding the honeybee waggle dance. In addition, we will work in partnership with the Scottish Beekeepers Association (SBA) on a 3-year survey of the impact of environmental chemicals on colony performance. SBA members will also support our data collection with regard to honeybee foraging. This project is a unique opportunity to develop a network of UK scientists with complementary skills and shared goals to address the issues of insect pollinator loss.