Sound and vibration: production and perception

许多动物使用声音和振动来相互交流，吸引配偶或建立领地。它们还用它们来探测捕食者和寄生虫，即使它们试图隐身，也不可避免地发出一些声音或振动。由于检测这些信号通常是生死攸关的事情，动物已经进化出了非常敏锐的感觉系统。另一方面，他们也开发了不同的技术，当他们互相交流时，他们会非常大声。我所提议的研究试图以昆虫和蜘蛛为模型系统，了解感知和生产系统的机械设计和神经生物学。 我的研究计划有三个主要主题。在第一个主题中，我将研究一个称为主动听觉放大的过程。主动放大由听觉感觉细胞进行。细胞通过产生自己的机械运动来选择性地放大某些信号。关于这个过程如何工作有不同的假设，这个项目将提供证据，帮助我们区分这些假设。通过阐明其分子机制，也将有助于我们对这一过程的进化起源提出假说。我将使用一种名为光学相干断层扫描（OCT）的新技术，测量不同昆虫完整且功能齐全的听觉器官内的细胞运动。在第二个主题中，我将研究蜘蛛振动传感器如何工作。蜘蛛使用一种叫做狭缝感受器的器官来感受震动。裂缝感器看起来像外骨骼上的裂缝，集中在腿关节周围。当蜘蛛经历振动时，它的关节会弯曲很小的量，这些力会传递到感受器。然而，这种传输是如何工作的尚不清楚。有两种假设，一种是腿内的结构传递弯曲力，另一种是腿内的压力变化传递力。但没有直接证据表明这两种机制。使用OCT系统，我们将能够通过测量腿部管腔的压力和关节结构的振动来提供这一证据。在最后一个主题中，我将研究蟋蟀和纺织娘的鸣叫行为。考虑到它们的大小，两者都不能有效地产生声音，但它们的歌声却完全不同。蟋蟀扬起翅膀唱歌，而纺织娘则把翅膀贴在身体上。Katydid的翅膀看起来也很不同，不像蟋蟀，它们被包裹起来看起来像叶子。我将使用振动测量和声学建模来测试是否katydid模式的歌唱发展，以提高他们的歌唱效率或他们的伪装。我提出的研究将回答关于这些微型传感器的设计和神经生物学的重要问题，这些微型传感器是节肢动物通过进化完善的，并且在为传感器设计提供仿生灵感方面非常有用。

Many animals use sound and vibration to communicate with each other, to attract mates or to establish territories. They also use them to detect their predators and parasites, who inevitably make some sound or vibration even when they are trying to be stealthy. Since detecting these signals is often a matter of life-and-death, animals have evolved sensory systems that are exquisitely acute. On the other hand they have also developed different techniques of being very loud when they communicate with each other. The research that I am proposing seeks to understand the mechanical design and neurobiology of both the perception and production systems using insects and spiders as model systems. There are three main themes to my research programme. In the first theme, I will study a process called active auditory amplification. Active amplification is carried out by auditory sensory cells. The cells selectively amplify some signals over others by generating their own mechanical motion. There are different hypotheses about how this process works, and this project will provide evidence that will help us differentiate between these hypotheses. By illuminating the molecular mechanism, it will also help us develop hypothesis about the evolutionary origin of this process. I will use a new technique called optical coherence tomography (OCT) and measure cell motion inside the intact, and fully functioning auditory organs of different insects. In the second theme, I will study how spider vibration sensors work. Spiders use organs called slit sensilla for sensing vibrations. Slit sensilla appear like cracks in the exoskeleton and are concentrated around leg joints. When a spider experiences vibrations, its joints are bent by very small amounts and these forces are transmitted to the sensilla. How this transmission works, however is unknown. There are two hypotheses, one that structures inside the leg transmit the bending forces and the other that pressures changes inside the leg transmit the forces. But there is no direct evidence of either mechanism. Using the OCT system, we will be able to provide this evidence, by measuring the leg lumen for pressure and the joint structures for vibrations. In the last theme, I will study the singing behaviour of field crickets and katydids. Given their size, both are inefficient at producing sound, but they sing quite differently. Crickets sing with their wings raised and katydids with their wings held against the body. Katydid wings also look quite different, unlike crickets they are camouflaged to look like leaves. I will use vibration measurements and acoustic modelling to test whether the katydid mode of singing developed to improve their singing efficiency or their camouflage. The research I propose will answer important questions about the design and neurobiology of these miniature sensors that arthropods have perfected through evolution and will be very useful in providing biomimetic inspiration for sensor design.