Collaborative Research: Testing the consequences of wing flexibility to comprehensive flight performance in freely flying insects

昆虫的飞行性能在许多方面可以与鸟类、蝙蝠和人造飞机匹敌或超越；然而，与其他群体不同的是，昆虫对翅膀的三维形状几乎没有主动控制能力。昆虫的翅膀在飞行过程中被动地弯曲和扭曲，直到最近，人们才知道这些翅膀变形是超轻、拍打翅膀的不可避免的缺点，还是翅膀进化到弯曲的方式有利于飞行性能。最近的研究表明，柔性机翼可以产生比刚性机翼更高的空气动力，但灵活性对飞行性能的其他方面的影响尚不清楚。在这项研究中，研究人员将使用一种强大的新技术来加固活大黄蜂和泥瓦工蜂的翅膀，并对飞行性能的几个方面进行测试，包括最大发力、效率、在多风环境中的稳定性和机动性，以对昆虫翅膀的灵活性和设计有更全面的了解。此外，机身尺寸对机翼灵活性和飞行性能的影响将被量化。这项工作将具有广泛的意义，并刺激未来在生物力学、动物行为、进化、物理学和机器人技术方面的研究。该项目将为两个机构的本科生、研究生和博士后研究人员提供培训，一个是小型文理学院，另一个是大型、多元化的公立大学。此外，为了解决女性科学家在更高职业阶段的代表性下降的问题，将招募五名早期职业的女性生物力学家进行为期三年的同伴指导计划。最近的研究表明，柔性昆虫翅膀的被动变形可以增强气动力的产生。然而，灵活性对涉及更复杂环境或行为的飞行性能的其他方面的影响很少受到关注，因为这些很难用计算或物理建模方法模拟。在这项研究中，研究人员开发了一种技术，可以在不增加显著质量的情况下改变超轻昆虫翅膀的刚度（通过“夹板”柔性翼静脉关节），同时还将对飞行性能的多个方面进行测试，以更全面地了解翅膀的灵活性和设计。该项目有三个主要目标：(1)测试大黄蜂的弦向机翼灵活性如何影响飞行性能的所有主要方面，包括最大力量产生、能量效率、非定常流动稳定性和自主跟踪和避碰时的机动性；(2)检查展向与弦向灵活性对梅森蜜蜂的力量产生和能量效率的相对重要性；(3)探索弹性对被动机翼变形和最大力产生的影响如何随大黄蜂的大小而变化。这项工作将产生广泛的影响，并促进未来在许多领域的研究，并将为本科生、研究生和博士后提供培训。研究人员还将创建一个指导计划，旨在解决“管道泄漏”现象，目标是五名早期职业女性生物力学家参加一个为期三年的同行指导圈，该圈将提供每月的讨论，反馈和支持，以及参加年度生物力学会议的资金。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many aspects of insect flight performance rival or surpass that of birds, bats, and man-made aircraft; yet unlike these other groups, insects have little active control over the three-dimensional shape of their wings. Insect wings bend and twist passively during flight, and until recently it wasn't known whether these wing deformations are an inevitable drawback of ultra-light, flapping wings, or whether wings have evolved to bend in ways that benefit flight performance. Recent studies have shown that flexible wings can produce higher aerodynamic forces than stiff ones, but the effects of flexibility on other aspects of flight performance remain unknown. In this study, a powerful new technique developed by the researchers to stiffen the wings of live bumblebees and mason bees will be used, along with tests of several aspects of flight performance, including maximum force production, efficiency, stability in windy environments, and maneuverability, to develop a more comprehensive understanding of wing flexibility and design in insects. In addition, the effects of body size on wing flexibility and flight performance will be quantified. This work will have broad implications and spur future research in biomechanics, animal behavior, evolution, physics, and robotics. The project will provide training for undergraduate and graduate students and post-doctoral researchers at two institutions, a small liberal arts college and a large, diverse, public university. In addition, to address the declining representation of female scientists at higher career stages, five early-career, female biomechanists will be recruited for a three-year peer mentoring program. Recent studies have shown that the passive deformations of flexible insect wings can enhance aerodynamic force production. However, the effects of flexibility on other aspects of flight performance involving more complex environments or behaviors have received little attention, as these are difficult to simulate with computational or physical modeling approaches. In this study, a technique developed by the investigators to alter the stiffness of ultra-light insect wings without adding significant mass (by "splinting" a flexible wing-vein joint) will be used, along with tests of multiple aspects of flight performance, to develop a more comprehensive understanding of wing flexibility and design. This project has three main goals: (1) test how chordwise wing flexibility in bumblebees affects all major aspects of flight performance, including maximum force production, energetic efficiency, stability in unsteady flow, and maneuverability during voluntary tracking and collision avoidance, (2) examine the relative importance of spanwise versus chordwise flexibility to force production and energetic efficiency in mason bees, and (3) explore how the effects of flexibility on passive wing deformations and maximum force production vary with size in bumblebees. This work will have broad implications and spur future research in numerous fields, and will provide training for undergraduate and graduate students and post-doctoral fellows. The researchers will also create a mentoring program aimed at addressing the "leaky pipeline" phenomenon, targeting five early-career, female biomechanists to participate in a three-year peer mentoring circle that will provide monthly discussions, feedback, and support, as well as funding to attend an annual biomechanics conference.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.