Variation in circulating corticosterone levels is associated with altitudinal range expansion in a passerine bird
Variation in circulating corticosterone levels is associated with altitudinal range expansion in a passerine bird
复制标题
DOI：
10.1007/s00442-011-2001-5
复制
发表时间：
2011-10-01
期刊：
影响因子：
2.7
通讯作者：
Wingfield, John C.
中科院分区：
文献类型：
--
作者：
Addis, Elizabeth A.;Davis, Jason E.;Wingfield, John C.
生物体经常需要调整生理机制才能在新的栖息地成功繁殖。为了探索一些种群如何在生理上适应新的环境条件，而另一些种群则不适应，我们研究了白冠麻雀的三个亚种，白斑麻雀Zonotrichia leucophrys。在过去的60年里，这些亚种中的Z.L.pugetensis已经将其繁殖范围扩大到了高海拔地区。我们通过比较只在高海拔繁殖的甘贝母、只在低海拔繁殖的坚果泽兰、在低海拔繁殖的普氏泽兰和现在在高海拔繁殖的普氏泽兰种群之间的糖皮质激素循环水平，来研究对高海拔条件的生理适应。糖皮质激素调节生理和行为对环境条件的反应，是结构性分泌的，但也可以兼性释放。我们假设糖皮质激素皮质酮(CORT)的升高可能有助于在高海拔环境中繁殖。我们通过比较低海拔育种亚种普吉特和纳塔利亚种与高海拔育种亚种普吉特和L亚种的基线水平和应激诱导的CORT水平来验证这一假说。我们发现，在高海拔繁殖的种群表现出更高的基线和应激诱导的皮质醇水平。此外，我们还发现普氏泽兰在胁迫诱导的皮质醇反应中表现出更大的变异。这些结果表明，激素机制的调节在促进高海拔环境下的繁殖方面具有重要意义，这些机制的变化可能与促进海拔范围的扩大有关。
Organisms frequently need to adjust physiological mechanisms to successfully breed in novel habitats. To explore how some populations physiologically acclimate to novel environmental conditions while others do not, we examine three subspecies of the white-crowned sparrow, Zonotrichia leucophrys. Of these subspecies, Z. l. pugetensis has expanded its breeding range to high altitude over the last 60 years. We investigate physiological acclimation to high altitude conditions by comparing circulating levels of glucocorticoids among Z. l. gambelii, which only breeds at high altitude, Z. l. nuttalli, which only breeds at low altitude, a population of Z. l. pugetensis that breeds at low altitude, and a Z. l. pugetensis population that now breeds at high altitude. Glucocorticoids mediate physiological and behavioral responses to environmental conditions and are constitutively secreted, but can also be released facultatively. We hypothesized that elevation of the glucocorticoid corticosterone (CORT) may facilitate breeding in high altitude environments. We tested this hypothesis by comparing baseline and stress-induced CORT levels of subspecies breeding at low altitude, Z. l. pugetensis and Z. l. nuttalli, to subspecies breeding at high altitude, Z. l. pugetensis and Z. l. gambelii. We found that populations breeding at high altitude exhibit higher baseline and stress-induced levels of CORT. Additionally, we found that Z. l. pugetensis exhibit greater variation in the stress-induced CORT response. These results suggest an importance of modulation of hormonal mechanisms in facilitating breeding in high altitude environments, and that variation in these mechanisms may be associated with facilitating altitudinal range expansion.