Seasonal Adaptations in the Breathing Mechanics of High Arctic Ptarmigan.

岩雷鸟（Lagopus mutus）栖息在北方的高山地区。这些鸟类的一个亚种只在挪威的斯瓦尔巴特群岛的高北极岛屿上发现，季节性存款非常大量的身体脂肪。这种脂肪是北极冬季的紧急能量储备，因为极端天气加上永久的黑暗，这些鸟类反复面临可能致命的完全饥饿时期。在夏季，这些鸟的体重通常不到0.5公斤，但在秋季，它们的体重翻了一番，达到1公斤左右，身体脂肪占体重的30%以上。这种对高北极条件下生活的适应对这些动物来说是一个重大的生理挑战，不仅是提供资源来存款如此大量的脂肪，而且还与相对较大的额外体重一起发挥作用。Codd实验室最近证明，在肋骨上发现的辅助呼吸结构（钩突）分别作为肋骨和胸骨向前和向下运动的杠杆，当鸟吸气时，也作为肌肉的机械支柱，当鸟呼气时将胸骨拉起来。有趣的是，这些结构的长度取决于鸟是否适应跑步，飞行或潜水。岩雷鸟有独特的钩状突起，这表明它们的通风机制可能有根本的不同。此外，由于在冬季，额外的质量主要沉积在乳房肌肉组织和腹部周围，呼吸运动也可能受到严重影响。我们认为L. M. hyperboreus将表现出呼吸适应性，可能是新的辅助呼吸肌肉和骨盆抽吸的招募，以在他们的身体质量高时使他们的肺通气。我们将使用肌电图来确定目标肌肉在通气或运动过程中是否活跃。将记录锁骨间和腹部气囊压力，并使用视频录像监测运动。对于代谢功率，我们将使用呼吸测定法。将进行实验的北极生物学系（特罗姆瑟大学）为在自然条件下维持雷鸟殖民地做好了充分的准备;专业知识和设施在英国是不可用的。对雷鸟呼吸机制的研究将是迷人的，并为鸟类呼吸的复杂性提供新的线索。我们的研究将是第一个确定身体质量季节性波动对鸟类呼吸机制的影响的研究。

Rock Ptarmigan (Lagopus mutus) inhabit the alpine regions of the northern hemisphere. A sub species of these birds found only on the high arctic islands of Svalbard, Norway seasonally deposit very large amounts of body fat. This fat serves as emergency stores of energy for the arctic winter when these birds repeatedly face potentially lethal periods of total starvation, due to extreme weather in combination with permanent darkness. In summer these birds normally weigh less then 0.5kg but during autumn their mass doubles to around 1kg, with body fat making up more than 30% of their body weight. This adaptation to life in high arctic conditions represents a significant physiological challenge for these animals, not only in providing the resources to deposit such a large amount of fat but also functioning with the relatively large extra body mass. The Codd lab has recently demonstrated that accessory breathing structures found on the ribs (uncinate processes) act as levers for the forward and downward movement of the ribs and sternum, respectively, when the bird is breathing in and also as a mechanical strut for muscles to pull the sternum up when the bird breathe out. Interestingly these structures vary in length depending if the bird is adapted to running, flying or diving. The rock ptarmigan have unique uncinate processes which suggest there may be fundamental differences in their mechanics of ventilation. Moreover, because during winter the additional mass is primarily deposited around the breast musculature and abdomen, respiratory movements may also be severely affected. We believe that L. m. hyperboreus will demonstrate respiratory adaptations that may the recruitment of novel accessory breathing muscles and pelvic aspiration to ventilate their lungs when their body mass is high. We will use electromyography to determine whether target muscles are active during ventilation or locomotion. Interclavicular and abdominal air sacs pressure will be recorded and locomotion will be monitored using video footage. For metabolic power we will use respirometry. The Department of Arctic Biology (University of Tromso) where experiments will take place is well set up for the maintenance of ptarmigan colonies under natural conditions; expertise and facilities which are not available in the UK. Examination of the breathing mechanics of ptarmigan will be fascinating and shed new light on the complexities of avian respiration. Our study will be the first to determine the effect of seasonal fluctuations in body mass to the mechanics of breathing in birds.