Insect wing design: evolution and biomechanics

昆虫翅膀设计：进化和生物力学

基本信息

批准号：
EP/H004025/1
负责人：
Richard Bomphrey
金额：
$ 150.82万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FH004025%2F1
关键词：
Insect wing design evolution biomechanics

项目摘要

Insects are the most diverse order of animals on earth and flight may be the key to this success. However, despite hundreds of millions of years of evolution, insect wings have not converged on a single optimal shape. Instead, there is an extraordinary range of wing morphologies visible in the world today (and even more fossilized), yet fundamentally, they all perform the same task - to enable flight. This led me to ask 'why is there no single wing shape that is best-suited to flapping flight?'The answer may well lie in assorted locally optimal solutions, specifically adapted to the tasks each insect undertakes during its life. The mission-profile of flight is unique for each insect species and so the selection pressures on wing morphology and kinematics is also species specific. A dragonfly that catches its prey on the wing and engages in aerial combat against rivals must be fast and manoeuvrable. Contrast this with the death's-head hawkmoth, migrating across Europe raiding bees' nests. They must be highly efficient since energy is at a premium during migration, but also robust enough to withstand attacks from bees when in their honey-stores. Understanding the morphologies of over a million described flying insect species is unfeasible, yet trends run through them which are exciting for aerodynamic engineering because they show solutions to specific requirements that have been tried, tested, and proven to succeed.My research seeks to understand how and why insect wing shapes have such variation despite intense selective pressure for aerodynamic performance, and why morphologies change when transitioning between ecological niches. The best way to examine this is to look at examples of convergent evolution, species which have similar ecology and morphology, yet originate from disparate taxonomic branches. Selecting species which are quite unrelated from one another allows discrimination of the aspects of wing shape which are part of design optimisation as opposed to those which are simply due to their historical starting point. My experiment therefore utilizes a comparative approach to evaluate representative species from across the class.In Track 1 of my research programme, a Postdoc will measure the aerodynamic output of flying insects directly, because it is essential to know how fast and in which direction the air is moving around the wings and in the wake. Flow velocities will be calculated around insects tethered in a wind tunnel by seeding the air with a light fog, and illuminating the particles with pulsing laser light. This technique is called Digital Particle Image Velocimetry and is the technique of choice for engineers studying complex flows. Recently, I successfully applied the technique to flying insects despite their small size and high wingbeat frequencies.Insects have no musculature in their wings. All the deforming complexities of the flapping cycle are controlled either actively by muscles at the wing hinge, or passively by inertial and aerodynamic forces on the wing architecture. The aerodynamic output is a result of wing motion so it is vital to know how the wing shape changes during flapping. In Track 2 of my research, a PhD student will record the kinematics of individuals from the same representative insects. The student will test predictions about the role of wing shape in ecology, by artificially selecting strains of fruit fly for alternate morphologies (e.g. more slender wings) and characterising the new morphs' flight performance. Simultaneously, the student will validate their results, by selecting strains based upon flight performance, and measuring the resulting modification in wing morphology.The output from these two tracks will be: 1) an explanation for the diversity of insect wing shapes from the perspective of biomechanical adaptation; 2) detailed kinematic data for Computational Fluid Dynamics studies; 3) clear design guidelines for engineers constructing insect-sized vehicles.

昆虫是地球上最多样化的动物，飞行可能是这一成功的关键。然而，尽管有数亿年的进化，但昆虫的翅膀并未以单一最佳形状融合。取而代之的是，当今世界上看到的翼形态很广泛（甚至更具化石），但从根本上讲，它们都执行相同的任务 - 可以实现飞行。这使我问：“为什么没有最适合飞行的单翼形状？”答案很可能在各种本地最佳解决方案，特别适合每种昆虫在其生命中承担的任务。每种昆虫物种的飞行任务都是独特的，因此机翼形态和运动学的选择压力也是特定于物种的。一只在翅膀上捕获猎物并与竞争对手进行空中战斗的蜻蜓必须快速且可操纵。将其与死亡的霍克莫斯（Hawkmoth）进行对比，迁移到欧洲袭击蜜蜂的巢穴中。它们必须高效，因为在迁移过程中能源处于溢价状态，但在蜂蜜商店中的蜜蜂中也足以承受蜜蜂的攻击。了解超过一百万个描述的飞行昆虫物种的形态是不可行的，但是趋势贯穿于空气动力学工程方面令人兴奋，因为它们显示出对特定需求的解决方案，这些需求已被尝试，测试和证明是成功的。我的研究试图了解昆虫翼的形状以及为什么在空气动力学表现上的选择性变化，而在自动化性绩效中的选择性变化，而在变化之间会改变态度。检查这一点的最佳方法是研究收敛进化的实例，具有相似生态学和形态的物种，但源于不同的分类分支。选择彼此无关的物种可以歧视翼形的各个方面，这是设计优化的一部分，而不是仅仅是由于其历史起点而引起的。因此，我的实验利用了一种比较方法来评估整个类别的代表性物种。在我的研究计划的轨道1中，博士后将直接测量飞行昆虫的空气动力学输出，因为必须了解空气在翅膀周围和尾随的方向上的速度以及在哪个方向上移动。流速度将通过用光雾播种空气，并用脉冲激光照明颗粒来计算在风洞中的昆虫上计算的流速。该技术称为数字粒子图像速度法，是研究复杂流量的工程师的首选技术。最近，尽管它们的尺寸很小，而且机翼频率很高，但我还是成功地将该技术应用于飞行昆虫。拍打周期的所有变形复杂性均由翼铰链处的肌肉积极控制，或者由机翼结构上的惯性和空气动力被动地控制。空气动力学输出是机翼运动的结果，因此重要的是要知道翅膀形状在拍打过程中如何变化。在我的研究的轨道2中，博士生将记录来自同一代表性昆虫的个体的运动学。学生将通过人工选择替代形态的果蝇菌株（例如，更多细长的翅膀）来测试有关翅膀形状在生态学中的作用的预测，并表征了新的形态的飞行性能。同时，学生将通过基于飞行性能选择菌株并测量机翼形态的修饰来验证其结果。这两个曲目的输出将是：1）从生物力学适应的角度来解释昆虫机翼形状多样性的解释； 2）用于计算流体动力学研究的详细运动学数据； 3）针对建造昆虫大小的车辆的工程师的清晰设计指南。