Comparative Mechanics of Rapid Predatory Movements

即使是最有力的肌肉收缩也太慢，距离也太短，无法达到我们在许多动物的快速掠食性运动中看到的令人难以置信的速度和加速度。人类利用像弩这样的工程系统规避了这些限制，在弩中，缓慢的手臂运动通过弓的弹性能量储存和闩锁的快速能量释放转化为快速的箭运动。在进化史上，动物已经通过类似于弓箭的力量放大机制克服了肌肉收缩的限制，然而科学家们对这些系统的进化变化与力量放大的潜在物理原理之间的相互作用缺乏广泛的理解。这个研究项目的重点是螳螂虾（口足目动物），它在动物王国中产生最快和最有力的掠食性运动。猛禽的攻击发生在几毫秒内，速度可以达到20米/秒以上；有些物种可以以超过1000牛（其体重的数千倍）的冲击力进行撞击。这些令人印象深刻的动作是由缓慢收缩的肌肉控制的，这些肌肉激活了一个能量放大结构网络，包括弹簧、锁扣、连杆和杠杆臂。这种力量放大系统在450种口足类动物中都是保守的，然而它们的猛禽附属物却非常多样化，从带刺的长矛到斧头和锤子。为了解决生物功率放大的广泛进化模式和基本物理原理，本项目整合了三种方法：(1)跨物种形态和性能的生理和运动学分析；(2)应用一个模型，该模型集成并解释了弹簧、连杆和杠杆臂在功率放大和性能中的相对作用；(3)将模型变量的动态变化与物种间的实际变化进行对比分析。通过生理学、物理学和进化模式的整合，这项研究的结果将为一般的生物功率放大系统提供基本的见解。该提案的更广泛影响包括它是综合性的，结合了生物学和工程学原理，并侧重于培训和教育包括女性和代表性不足的少数民族在内的不同群体的学生。这项研究的结果将通过nsf资助的项目（例如，理解进化）以及与科学出版社的合作向公众提供。

Even the most powerful muscles contract too slowly and over distances too short to achieve the incredible speeds and accelerations that we see in the many rapid predatory movements of animals. Humans circumvent these limitations with engineered systems like the crossbow, in which slow arm movement is transformed into rapid arrow movement through the elastic energy storage of the bow and rapid energy release via a latch. Repeatedly over evolutionary history, animals have overcome the limits of muscle contractions through power amplification mechanisms similar to that of the bow and arrow, and yet scientists lack a broad understanding of the interplay between the evolutionary variation in these systems and the underlying physical principles of power amplification. This research project focuses on mantis shrimp (Stomatopoda), which generate among the fastest and most forceful predatory movements in the animal kingdom. Raptorial strikes occur within several milliseconds and can reach speeds of over 20 m/s; some species can strike with impact forces of over 1000 N (thousands of times their body weight). These impressive movements are controlled by slowly contracting muscles that activate a network of power amplification structures including springs, latches, linkages and lever arms. This power amplification system is conserved across the 450 species of stomatopods, yet their raptorial appendages are remarkably diverse, ranging from spiny and barbed spears to hatchets and hammers. To address the broad evolutionary patterns and the fundamental physical principles of biological power amplification, this project integrates three approaches: (1) physiological and kinematic analyses of morphology and performance across species; (2) application of a model that integrates and accounts for the relative roles of springs, linkages and lever arms in power amplification and performance; and (3) comparative analyses of the dynamics of the model variables compared to their actual variation observed across species. Through the integration of physiology, physics and evolutionary patterns, the results of this research will provide fundamental insights into biological power-amplified systems, in general. The broader impacts of this proposal include that it is integrative, combines biology and engineering principles, and focuses on the training and education of a diverse group of students including women and underrepresented minorities. The findings from this research will be provided to the public through NSF-funded programs (e.g., Understanding Evolution) and collaborations with the scientific press.