Romero L M, Soma K K, O'Reilly K M, Suydam R, Wingfield J C
Department of Zoology, University of Washington, Seattle 98195, USA.
Horm Behav. 1998 Feb;33(1):40-7. doi: 10.1006/hbeh.1997.1432.
We examined hormonal profiles and behavior associated with maintaining a single-purpose territory in an Arctic-breeding songbird-the snow bunting (Plectrophenax nivalis). Snow buntings differ from many other Arctic-breeding passerines by using nest cavities, an uncommon and defended resource, but not relying upon the surrounding territory for forage. Circulating levels of testosterone in males were high when territories were established and then decreased over the breeding season. LH secretion was enhanced in females while laying eggs, followed by detectable levels of estradiol during incubation. Both sexes showed equivalent corticosterone responses to the stress of being captured and held. Male snow buntings vigorously defended territories in response to a simulated territorial intrusion both when initiating breeding and when feeding young. Exogenous testosterone implants surprisingly inhibited physical aggression but enhanced singing when birds were feeding young, thus suggesting that song and physical aggression are mediated by different hormonal mechanisms at this time of year. Together, these results contrast with hormonal profiles and behavior in other Arctic-breeding passerines.
我们研究了与在北极繁殖的鸣禽——雪鹀（Plectrophenax nivalis）中维持单一用途领地相关的激素水平和行为。雪鹀与许多其他北极繁殖的雀形目鸟类不同，它们使用巢洞，这是一种不常见且受保护的资源，但不依赖周围领地觅食。雄性在建立领地时睾酮的循环水平较高，然后在繁殖季节下降。雌性在产卵时促黄体生成素分泌增强，随后在孵化期间可检测到雌二醇水平。两性对被捕获和扣留的应激表现出相同的皮质酮反应。雄性雪鹀在开始繁殖和喂养幼鸟时，都会对模拟的领地入侵做出强烈的领地防御反应。令人惊讶的是，外源睾酮植入物抑制了身体攻击行为，但在鸟类喂养幼鸟时增强了鸣叫，因此表明在一年中的这个时候，鸣叫和身体攻击行为是由不同的激素机制介导的。这些结果与其他北极繁殖雀形目鸟类的激素水平和行为形成了对比。
