The endocrine mechanism regulating stopover refueling and departure in avian migrants

对于成功完成迁徙并及时到达繁殖地或越冬地的鸟类来说，需要在中途站快速补充燃料，并在适当的时间离开中途站。虽然影响加油和离开中途停留速度的因素是众所周知的，但我们对这些关键过程中涉及的生理机制的理解甚至识别是非常有限的。我建议大幅增加对鸟类迁徙的关键行为——加油和离开中途站——所涉及的内分泌机制的有限认识。首先，通过操纵循环皮质酮水平，我将测试皮质酮与加油率和中途停留离场可能性之间观察到的相关性的因果关系。其次，我将研究ghrelin激素是否参与了准备离开的移民体内皮质酮水平的上调。具体来说，我将确定是否a)皮质酮和胃饥饿素水平在中途停留的移民中呈正相关，b)胃饥饿素水平在离开中途停留时增加。

In birds successful completion of migration and timely arrival at the breeding or wintering grounds requires rapid refueling at stopover sites and departing from stopover at the appropriate time. Whereas the factors influencing the rate of refueling and departure from stopover are well known, our understanding, and even identification, of the physiological mechanism(s) involved in these crucial processes is very limited. I propose to substantially increase the limited knowledge of the endocrine mechanisms involved in refueling and departure from stopover, key behaviors of avian migration. First, by manipulating circulating corticosterone level I will test the causality of the correlations observed between corticosterone and both refueling rate and stopover departure likelihood. Second, I will investigate whether the hormone ghrelin is involved in up-regulating corticosterone level in migrants that are ready to depart. Specifically, I will determine whether a) corticosterone and ghrelin levels are positively correlated in migrants at stopover, and b) ghrelin levels increase towards departure from stopover.