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都可以与鸟类、蝙蝠和人造飞机相媲美或超越；但与其他类群不同的是，昆虫几乎无法主动控制它们翅膀的三维形状。昆虫的翅膀在飞行中被动弯曲和扭曲，直到最近，人们还不知道这些翅膀变形是否是超轻拍打翅膀的不可避免的缺点，或者翅膀是否进化成了有利于飞行性能的弯曲方式。最近的研究表明，柔性机翼可以产生比刚性机翼更高的气动力，但柔性对飞行性能的其他方面的影响尚不清楚。在这项研究中，研究人员将使用研究人员开发的一种强大的新技术来加强活熊蜂和石蜂的翅膀，并对飞行性能的几个方面进行测试，包括最大作用力、效率、在多风环境中的稳定性和机动性，以更全面地了解昆虫的翅膀灵活性和设计。此外，还将量化机身尺寸对机翼灵活性和飞行性能的影响。这项工作将具有广泛的意义，并推动未来在生物力学、动物行为、进化论、物理学和机器人方面的研究。该项目将在两个机构为本科生和研究生以及博士后研究人员提供培训，这两个机构分别是一所小型文理学院和一所大型、多样化的公立大学。此外，为了解决女性科学家在较高职业阶段的代表性下降的问题，将招募五名职业生涯早期的女性生物机械师参加为期三年的同行指导计划。最近的研究表明，昆虫柔性翅膀的被动变形可以提高空气动力的产生。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，因为这些方面很难用计算或物理建模方法进行模拟。在这项研究中，研究人员开发了一种技术，在不增加显著质量的情况下改变超轻型昆虫翅膀的硬度(通过对柔性翅膀-静脉关节进行夹板)，以及对飞行性能的多个方面的测试，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)测试大黄蜂弦向翅膀灵活性如何影响飞行性能的各个主要方面，包括最大作用力产生、能量效率、非定常流动中的稳定性，以及在自愿跟踪和避碰期间的机动性；(2)研究跨向和弦向灵活性对Mason蜜蜂的作用力和能量效率的相对重要性；以及(3)探索柔性对大黄蜂被动翅膀变形和最大作用力产生的影响如何随大小而变化。这项工作将具有广泛的影响，并将刺激未来在许多领域的研究，并将为本科生和研究生以及博士后研究员提供培训。研究人员还将创建一个旨在解决“泄漏管道”现象的指导计划，目标是五名职业生涯早期的女性生物机械师参加一个为期三年的同行指导圈，该圈子将每月提供讨论、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NSF的法定使命，并通过使用基金会的智力优势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.