Physiological Adaptation and Phylogenetic Constraints on Reproduction in Antarctic Birds

许多种类的南极鸟类的成鸟都表现出对寒冷环境的形态、生理和行为适应。然而，尚不清楚成鸟和雏鸟是如何适应南极条件下成功存活和成长的。由于雏鸟生理不成熟、体型小、绝缘性差、缺乏机动性，因此面临着巨大的体温调节问题。内温发育是幼鸟个体发育过程中的一个重要事件，它深刻地影响着它们的父母的能量和繁殖。Bennett将使用三种轮状鸟类(海鸥、南极Skua和大牛嘴)来研究幼鸟的体温调节是否主要受成鸟和雏鸟的行为或发育中的幼鸟的生理能力的影响。这些鸟类独立地定居在南极洲，因此在生态上是趋同的。海带海鸥的分布范围延伸到较低的纬度，使物种内和物种之间的比较成为可能。将评估不同行为策略(包括筑巢、觅食模式和孵化行为)和生理适应(包括休息和最大耗氧量、电导、颤抖能力和骨骼肌酶活性)的相对能量成本和生存意义。这项研究将成为一项更大的研究的关键部分，该研究旨在研究轮状鸟类在生态压力下的发育进化。

The adults of many species of Antarctic birds show morphological, physiological and behavioral adaptations to their cold environment. However, it is not known how adults and chicks have adapted to enable successful chick survival and growth under Antarctic conditions. The thermoregulatory problems facing nestling birds are tremendous due to their immature physiology, small size, poor insulation and lack of mobility. The development of endothermy is a crucial event during the ontogeny of young birds, and it profoundly impacts the energetics and reproduction of their parents. Bennett will investigate whether thermoregulation of young chicks is primarily influenced by behavior of adults and chicks or the physiological capacity of the developing young, using three charadriiform bird species (Kelp Gull, Antarctic Skua, and Greater Sheathbill). These birds independently colonized Antarctica and are hence ecologically convergent. The Kelp Gull range extends to lower latitudes, enabling comparisons to be made both within and between species. The relative energetic costs and survival implications of different behavioral strategies (including nest construction, foraging patterns and brooding behavior) and physiological adaptations (including resting and maximal oxygen consumption, conductance, shivering capacity, and enzymatic activity in skeletal muscles) will be assessed. This study will form a critical part of a larger study of the evolution of development in charadriiform birds in response to ecological pressures.