美国佛罗里达大学Emma R. Schachner团队近期取得重要工作进展，他们研究提出，呼吸系统影响翱翔鸟类的飞行力学。相关研究成果2024年6月12日在线发表于《自然》杂志上。

据介绍，胸下憩室（SPD）是鸟类呼吸系统的延伸，位于负责拍打翅膀的主要肌肉之间。

研究人员调查了68种鸟类的肺器官，并表明SPD几乎存在于所有调查的翱翔类群中，但在非翱翔类群中不存在。研究人员发现，SPD这种结构独立演化了至少7次，表明憩室可能与飞行方式有着功能性和适应性的关系。使用飞鹰Buteo jamaicensis和Buteo swainsoni作为模型，研究人员表明SPD对于通风来说不是不可或缺的，膨胀的SPD可以增加胸肌颅骨部分的力臂，并且飞鹰的胸肌束明显短于非飞鹰。

SPD介导的胸肌杠杆作用的增加与力专用肌肉结构的耦合产生了一个气动系统，该系统适用于飞行中预期的等长收缩条件。呼吸系统在鸟类运动中的机械作用的发现突显了该器官系统的功能复杂性和异质性，并表明肺憩室可能具有其他未发现的次要功能。

总之，这些数据为SPD在翱翔谱系中的反复出现提供了机制解释，并表明呼吸系统可以被选择为应对飞行挑战提供生物力学解决方案，从而影响鸟类飞行能力的演化。

附：英文原文

Title: The respiratory system influences flight mechanics in soaring birds

Author: Schachner, Emma R., Moore, Andrew J., Martinez, Aracely, Diaz Jr, Raul E., Echols, M. Scott, Atterholt, Jessie, W. P. Kissane, Roger, Hedrick, Brandon P., Bates, Karl T.

Issue&Volume: 2024-06-12

Abstract: The subpectoral diverticulum (SPD) is an extension of the respiratory system in birds that is located between the primary muscles responsible for flapping the wing1,2. Here we survey the pulmonary apparatus in 68 avian species, and show that the SPD was present in virtually all of the soaring taxa investigated but absent in non-soarers. We find that this structure evolved independently with soaring flight at least seven times, which indicates that the diverticulum might have a functional and adaptive relationship with this flight style. Using the soaring hawks Buteo jamaicensis and Buteo swainsoni as models, we show that the SPD is not integral for ventilation, that an inflated SPD can increase the moment arm of cranial parts of the pectoralis, and that pectoralis muscle fascicles are significantly shorter in soaring hawks than in non-soaring birds. This coupling of an SPD-mediated increase in pectoralis leverage with force-specialized muscle architecture produces a pneumatic system that is adapted for the isometric contractile conditions expected in soaring flight. The discovery of a mechanical role for the respiratory system in avian locomotion underscores the functional complexity and heterogeneity of this organ system, and suggests that pulmonary diverticula are likely to have other undiscovered secondary functions. These data provide a mechanistic explanation for the repeated appearance of the SPD in soaring lineages and show that the respiratory system can be co-opted to provide biomechanical solutions to the challenges of flight and thereby influence the evolution of avian volancy.

DOI: 10.1038/s41586-024-07485-y

Source: https://www.nature.com/articles/s41586-024-07485-y