Neuroethology of odour-based navigation in aquatic gastropods

水生腹足动物基于气味导航的神经行为学

• 批准号: RGPIN-2020-05894
• 负责人: Wyeth, Russell
• 金额: $ 3.42万
• 依托单位: St. Francis Xavier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745951
• 关键词: Neuroethology; odour; based; navigation; aquatic

My long-term goal is to understand how animals use multiple navigation strategies to move, focusing on odour-based navigation in gastropods. Researchers have spent considerable effort to understand how animals respond to attractive odour plumes by crawling upstream, following the flow to an odour source. Yet, in nature, flow directions frequently change. We know much less about the consequences of this flow variability on animal navigation. My first objective is to explore how slow-moving slugs and snails cope with flow variability at two different levels: one that should be tracked, and another that likely should be ignored. First, as bulk flow direction shifts, so do odour plumes, and animals must track these shifts to find odour sources. My students and I will use field video recording and current meters to explore how responsive the nudibranch Tritonia diomedea is to shifting flows of varying degrees, empirically determining the time scale over which the slugs determine bulk flow direction. Second, depending on flow speeds, an odour plume carried by unchanging bulk flow will involve turbulence - smaller scale variations in flow direction generated by water movement across the substrate. If so, the animals should avoid following this local flow variation, responding only to the underlying bulk flow direction. For these experiments, we will use the freshwater snail Lymnaea stagnalis to test their responses to local turbulence. From the work on both species, we will learn how the animals may differentiate between changes in bulk flow direction versus changes from turbulent flow. My second objective is to lay a foundation to explore how the animals' nervous system produces these behaviours. The experimental amenability and simpler nervous system of gastropods allow us to determine the roles of single neurons in cue detection and the subsequent control mechanisms of the animals' crawling. However, there remains a substantial gap in our understanding of the sensory systems involved in navigation. Thus, my students and I will use a variety of methods to document the anatomy of the nervous system in the animals' sense organs. My third objective is to focus specifically on the function of the sensory neurons and circuits that detect and process flow direction in T. diomedea. This sensory processing must serve as a key input into the brain circuits that control navigation, yet we know very little about the detection of flow direction in any animal. Our results will guide future aspects of my research program studying the neural circuits that produce the different navigational strategies in gastropods. Moreover, by comparing results from across the animal kingdom, we can achieve a broader understanding of the neural mechanisms underlying both navigation and other behaviours. Finally, through this research, my students will learn a variety of fundamental skills and transferable techniques they can apply in their academic or professional careers.

我的长期目标是了解动物如何使用多种导航策略来移动，重点关注腹足动物基于气味的导航。研究人员花费了大量精力来了解动物如何通过向上游爬行、跟随流向气味源来对有吸引力的气味羽流做出反应。然而，在自然界中，流动方向经常发生变化。我们对这种流量变化对动物导航的影响知之甚少。我的第一个目标是探索移动缓慢的蛞蝓和蜗牛如何应对两个不同级别的流量变化：一个应该被跟踪，另一个可能应该被忽略。首先，随着总体流动方向的变化，气味羽流也会发生变化，动物必须跟踪这些变化才能找到气味源。我和我的学生将使用现场视频记录和海流计来探索裸鳃亚目 Tritonia diomedea 对不同程度的流动变化的反应程度，凭经验确定段塞决定整体流动方向的时间尺度。其次，根据流速，不变的整体流所携带的气味羽流将涉及湍流——水在基材上的运动产生的流动方向的较小规模的变化。如果是这样，动物应避免遵循这种局部流动变化，仅对潜在的整体流动方向做出反应。在这些实验中，我们将使用淡水蜗牛 Lymnaea stagnalis 来测试它们对局部湍流的反应。通过对这两个物种的研究，我们将了解动物如何区分总体流动方向的变化与湍流方向的变化。我的第二个目标是为探索动物的神经系统如何产生这些行为奠定基础。腹足动物的实验适应性和更简单的神经系统使我们能够确定单个神经元在线索检测中的作用以及动物爬行的后续控制机制。然而，我们对导航中涉及的感觉系统的理解仍然存在很大差距。因此，我和我的学生将使用各种方法来记录动物感觉器官中神经系统的解剖结构。我的第三个目标是特别关注 T. diomedea 中检测和处理流动方向的感觉神经元和电路的功能。这种感觉处理必须作为控制导航的大脑回路的关键输入，但我们对任何动物的流向检测知之甚少。我们的结果将指导我的研究计划的未来方面，研究腹足动物中产生不同导航策略的神经回路。此外，通过比较整个动物界的结果，我们可以更广泛地了解导航和其他行为背后的神经机制。最后，通过这项研究，我的学生将学习可以在学术或职业生涯中应用的各种基本技能和可转移技术。