Seasonal Adaptations in the Breathing Mechanics of High Arctic Ptarmigan.

北半球高山地区的松鸡(Lagopus Mutus)。这种鸟的一个亚种只在挪威斯瓦尔巴特群岛的北极高地上发现，季节性地储存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，由于极端天气和永久的黑暗，这些鸟反复面临潜在的致命的完全饥饿的时期。在夏天，这些鸟的体重通常不到0.5公斤，但到了秋天，它们的体重会翻一番，达到1公斤左右，体脂占它们体重的30%以上。这种对北极高地生活的适应对这些动物来说是一个重大的生理挑战，不仅是在提供储存如此大量脂肪的资源方面，而且在相对较大的额外身体质量下也是如此。Codd实验室最近证明，在鸟类吸气时，肋骨(钩突)上的附属呼吸结构分别充当肋骨和胸骨向前和向下移动的杠杆，也是鸟类呼气时肌肉向上拉起胸骨的机械支柱。有趣的是，这些结构的长度不同，取决于鸟是否适应跑步、飞行或潜水。松鸡有独特的钩状突起，这表明它们的通风机制可能有根本的不同。此外，由于冬季额外的肿块主要沉积在乳房肌肉和腹部周围，呼吸运动也可能受到严重影响。我们相信，当他们的体重较高时，他们会表现出呼吸适应，可能会重新招募新的辅助呼吸肌和盆腔吸气来呼吸他们的肺。我们将使用肌电图术来确定目标肌肉在换气或运动过程中是否活跃。将记录锁骨间和腹部气囊的压力，并使用视频监控移动情况。对于新陈代谢能力，我们将使用呼吸测量法。将进行实验的北极生物系(特罗姆索大学)为在自然条件下维护松鸡群体建立了良好的设施；英国没有的专业知识和设施。对松鸡呼吸机制的研究将令人着迷，并为了解鸟类呼吸的复杂性提供新的线索。我们的研究将首次确定体重的季节性波动对鸟类呼吸力学的影响。

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.