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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，飞行可能是成功的关键。然而，尽管经过数亿年的进化，昆虫的翅膀并没有集中在一个单一的最佳形状上。相反，在当今世界上，有一系列非凡的机翼形态可见（甚至更多），但从根本上说，它们都执行相同的任务-使飞行。这让我问：“为什么没有一种单一的翅膀形状最适合扑翼飞行？”“答案很可能在于各种局部最优解决方案，特别适合每种昆虫在其生命中承担的任务。飞行的任务轮廓对于每个昆虫物种是独特的，因此对翅膀形态和运动学的选择压力也是物种特异性的。一个在空中捕捉猎物并与对手进行空战的飞行器必须快速而灵活。相比之下，死亡的头天蛾，迁徙到欧洲各地袭击蜂巢。它们必须是高效的，因为在迁移过程中能量是非常宝贵的，但也必须足够强大，以抵御蜜蜂在其蜂蜜仓库中的攻击。了解超过一百万种描述的飞行昆虫的形态是不可行的，但趋势贯穿其中，这对空气动力学工程来说是令人兴奋的，因为它们显示了已经尝试过的特定要求的解决方案，测试，并证明是成功的。我的研究旨在了解昆虫翅膀形状如何以及为什么在空气动力学性能的强烈选择压力下会有这样的变化，以及为什么在生态位之间转换时形态会发生变化。检验这一点的最好方法是看看趋同进化的例子，即具有相似生态和形态的物种，但起源于不同的分类分支。选择彼此完全不相关的物种允许区分翼形的方面，这是设计优化的一部分，而不是那些仅仅是由于它们的历史起点。因此，我的实验采用了比较的方法来评估整个班级的代表性物种。在我的研究项目的第一轨道中，博士后将直接测量飞行昆虫的空气动力学输出，因为它必须知道空气在翅膀周围和尾流中移动的速度和方向。通过在空气中撒上一层轻雾，并用脉冲激光照射这些颗粒，可以计算出被拴在风洞中的昆虫周围的流速。这种技术被称为数字粒子图像测速技术，是工程师研究复杂流动的首选技术。最近，我成功地将这项技术应用于飞行昆虫，尽管它们的体型很小，翅膀振动频率很高。扑翼周期的所有变形复杂性要么由机翼铰链处的肌肉主动控制，要么由机翼结构上的惯性和气动力被动控制。空气动力输出是机翼运动的结果，因此了解扑翼过程中机翼形状的变化至关重要。在我的研究轨道2中，一名博士生将记录来自相同代表性昆虫的个体的运动学。学生将通过人工选择果蝇品系的替代形态（例如更细长的翅膀）并表征新形态的飞行性能来测试有关翅膀形状在生态学中的作用的预测。同时，学生将验证他们的结果，通过选择基于飞行性能的应变，并测量由此产生的翅膀形态的修改。这两个轨道的输出将是：1）从生物力学适应的角度解释昆虫翅膀形状的多样性; 2）计算流体动力学研究的详细运动学数据; 3）为建造昆虫大小车辆的工程师提供明确的设计指南。