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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目，飞行可能是其成功的关键。然而，尽管经过数亿年的进化，昆虫翅膀并没有收敛到单一的最佳形状。相反，当今世界上可见各种各样的翅膀形态（甚至更加化石），但从根本上说，它们都执行相同的任务 - 实现飞行。这让我问“为什么没有最适合扑动飞行的单一翅膀形状？”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一生中承担的任务。每个昆虫物种的飞行任务概况都是独特的，因此对翅膀形态和运动学的选择压力也是特定于物种的。用翅膀捕捉猎物并与对手进行空战的蜻蜓必须速度快且机动灵活。与此相比，死头天蛾在欧洲迁徙，袭击蜂巢。它们必须非常高效，因为在迁徙过程中能量非常宝贵，但它们也必须足够坚固，能够抵御蜜蜂在蜜库中的攻击。了解超过一百万种所描述的飞行昆虫物种的形态是不可行的，但贯穿其中的趋势对空气动力学工程来说是令人兴奋的，因为它们展示了经过尝试、测试和证明成功的特定要求的解决方案。我的研究旨在了解尽管空气动力学性能存在巨大的选择压力，但昆虫翅膀形状如何以及为何会出现这种变化，以及为什么在生态位之间转换时形态会发生变化。检验这一点的最佳方法是查看趋同进化的例子，这些物种具有相似的生态和形态，但起源于不同的分类分支。选择彼此完全不相关的物种可以区分机翼形状的各个方面，这是设计优化的一部分，而不是仅仅由于其历史起点而导致的机翼形状方面。因此，我的实验采用比较方法来评估整个班级的代表性物种。在我的研究计划的第一轨道中，博士后将直接测量飞行昆虫的空气动力学输出，因为了解空气在翅膀周围和尾流中移动的速度和方向至关重要。通过在空气中播撒光雾，并用脉冲激光照射颗粒，可以计算拴在风洞中的昆虫周围的流速。这种技术称为数字粒子图像测速，是研究复杂流动的工程师的首选技术。最近，我成功地将这项技术应用于飞行昆虫，尽管它们体积小且振翅频率高。昆虫的翅膀没有肌肉组织。扑动循环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力和空气动力被动控制。空气动力输出是机翼运动的结果，因此了解扑动过程中机翼形状如何变化至关重要。在我的研究的第二轨中，一名博士生将记录同一代表性昆虫个体的运动学。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，学生将通过根据飞行性能选择菌株并测量翅膀形态的变化来验证他们的结果。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) 用于计算流体动力学研究的详细运动学数据； 3）为工程师建造昆虫大小的车辆提供明确的设计指南。