An investigation into the bee's gustatory mechanisms for the detection of toxins in nectar

对蜜蜂检测花蜜中毒素的味觉机制的研究

• 批准号: BB/S000402/1
• 负责人: Geraldine Wright
• 金额: $ 57.94万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FS000402%2F1
• 关键词: investigation; into; bee; gustatory; mechanisms

Many animals, plants, and fungi defend themselves from being eaten by the production or sequestration of toxic chemicals. Thousands of these compounds have been identified from plants. For hungry animals, avoiding death or intoxication by defence compounds can be as important as identifying nutrients in food. Taste is the gatekeeper regulating food ingestion: it permits chemical identification and instructs the appropriate behavioural response. For example, before staring a meal, insects like bees sample food using gustatory receptors (Grs) expressed in neurons in hair-like sensilla on the mouthparts, antennae, and tarsi. If a toxic compound is detected in food, the insect will reject the food item and move on. Insects have often led the way to greater insight into neuronal mechanisms when they are used as model organisms for understanding how sensory systems function. Previous research has shown that the gustatory systems of vertebrates and insects are organized such that a subset of gustatory cells or neurons is excited by sugars and other nutrients, whereas others are excited by toxic (bitter) compounds. New research in insects, however, has revealed that some gustatory receptor neurons (GRNs) can be activated by both nutrients and potential toxins. A simple model, where the activity in sugar-sensing neurons evokes feeding and the activity in bitter-sensing neurons causes an insect to reject food may be incorrect. Instead, whole populations of GRNs are likely to be involved in encoding information. This has rarely been studied.Wright's laboratory is developing the bee as a model organism for understanding how taste functions. Bees have few gustatory receptor types, making it tractable to identify what they can detect and how their taste system functions. Research from her laboratory has shown that bees have poor acuity for the detection of potential toxins like pesticides in sugary solutions like nectar. It is unclear whether the sugars in these solutions mask the taste of the toxins, or whether the bees cannot detect the substances at all. The research proposed here will comprehensively study the responses of GRNs on the mouthparts of buff-tailed bumblebees to mixtures of sugars and non-nutrient compounds. We will measure how populations of these neurons respond to stimulation with several types of potential toxins including compounds naturally found in floral nectar. As a result of modern agriculture, bees are increasingly exposed to pesticides and other agrochemicals in floral pollen and nectar which they collect as food. For this reason, we will measure the detection thresholds of 3 additional bee species towards non-nutrient compounds including pesticides, fungicides, and herbicides. We will also perform behavioural assays to identify how the input from the GRNs instructs feeding behaviour. This research will be the first to characterize how an insect's gustatory system encodes the value of food when it is a mixture of nutrients and potential toxins. These experiments will also identify whether some bee species are better than others at detecting and avoiding toxins, providing data for land managers and policy makers regarding the risks of specific agrochemicals to bees when they are sprayed or delivered to flowering crops. In the future, this information could also be used to design new pesticides that permit bees to detect and avoid these flowers with nectar containing these compounds when such compounds are used to protect crops.

许多动物、植物和真菌通过生产或隔离有毒化学物质来保护自己不被吃掉。已经从植物中鉴定出数千种这种化合物。对于饥饿的动物来说，避免死亡或中毒的防御化合物可能与识别食物中的营养素一样重要。味觉是调节食物摄入的守门人：它允许化学识别并指导适当的行为反应。例如，在开始进食之前，蜜蜂等昆虫会使用味觉受体（Grs）对食物进行采样，味觉受体（Grs）表达在口器、触角和跗骨上毛发状感器的神经元中。如果在食物中检测到有毒化合物，昆虫将拒绝食物并继续前进。昆虫通常被用作理解感觉系统如何运作的模型生物，从而更深入地了解神经机制。先前的研究表明，脊椎动物和昆虫的味觉系统是这样组织的，即味觉细胞或神经元的一个子集被糖和其他营养素所兴奋，而其他人则被有毒（苦味）化合物所兴奋。然而，对昆虫的新研究表明，一些味觉受体神经元（GRNs）可以被营养物质和潜在毒素激活。一个简单的模型，其中糖敏感神经元的活动引起进食，而糖敏感神经元的活动导致昆虫拒绝食物可能是不正确的。相反，整个GRNs群体可能参与编码信息。赖特的实验室正在将蜜蜂作为了解味觉功能的模式生物。蜜蜂的味觉感受器类型很少，这使得识别它们能检测到什么以及它们的味觉系统如何发挥作用变得容易。她实验室的研究表明，蜜蜂在检测花蜜等含糖溶液中的农药等潜在毒素方面的灵敏度很差。目前还不清楚这些溶液中的糖是否掩盖了毒素的味道，或者蜜蜂是否根本无法检测到这些物质。本文提出的研究将全面研究黄尾熊蜂口器上GRNs对糖和非营养化合物混合物的反应。我们将测量这些神经元的数量如何对几种潜在毒素的刺激做出反应，包括花蜜中天然存在的化合物。由于现代农业的发展，蜜蜂越来越多地接触到作为食物的花粉和花蜜中的杀虫剂和其他农用化学品。因此，我们将测量另外3种蜜蜂对非营养化合物（包括杀虫剂、杀真菌剂和除草剂）的检测阈值。我们还将进行行为分析，以确定GRN的输入如何指导摄食行为。这项研究将首次描述昆虫的味觉系统如何编码食物的价值，当它是营养素和潜在毒素的混合物时。这些实验还将确定某些蜜蜂物种是否比其他蜜蜂更善于检测和避免毒素，为土地管理者和政策制定者提供有关特定农用化学品在喷洒或交付给开花作物时对蜜蜂的风险的数据。在未来，这些信息也可以用来设计新的杀虫剂，允许蜜蜂检测和避免这些含有这些化合物的花蜜的花朵，当这些化合物用于保护作物时。

项目成果

Temporal responses of bumblebee gustatory neurons to sugars.

• DOI: 10.1016/j.isci.2022.104499
• 发表时间: 2022-07-15
• 期刊: ISCIENCE
• 影响因子: 5.8
• 作者: Parkinson, Rachel H.;Kessler, Sebastien C.;Scott, Jennifer;Simpson, Alexander;Bu, Jennifer;Al-Esawy, Mushtaq;Mahdi, Adam;Miriyala, Ashwin;Wright, Geraldine A.
• 通讯作者: Wright, Geraldine A.

Mouthparts of the bumblebee (Bombus terrestris) exhibit poor acuity for the detection of pesticides in nectar.

• DOI: 10.7554/elife.89129
• 发表时间: 2023-12-18
• 期刊: eLife
• 影响因子: 7.7
• 作者: Parkinson RH;Scott J;Dorling AL;Jones H;Haslam M;McDermott-Roberts AE;Wright GA
• 通讯作者: Wright GA

Mouthparts of the bumblebee ( Bombus terrestris) exhibit poor acuity for the detection of pesticides in nectar

熊蜂（Bombus terrestris）的口器在检测花蜜中的农药方面表现出较差的敏锐度

• DOI: 10.1101/2023.02.03.526956
• 发表时间: 2023
• 作者: Parkinson R