Hormone - Behavior Adaptations for Breeding at High Latitudes

对于环境和社会因素，特别是领土侵略，如何影响北极候鸟的繁殖，人们知之甚少。在高纬度物种中，繁殖和环境诱导的压力之间的关系实际上是未知的，它们在其中起着重要的适应作用。许多物种到达北极，建立领地，并最终喂养它们的雏鸟，这只需要温带鸟类的一小部分时间。为了遵守这一严格的时间表，情侣们必须忽略在温带地区通常会抑制或延迟繁殖的环境条件。温菲尔德博士提出，北极鸟类的内分泌系统已经适应了这些限制。本研究建议继续研究两种潜在的拮抗激素之间的关系：皮质酮，它指导行为远离生殖活动和生存活动，睾丸激素，它介导与领土相关的攻击行为。温菲尔德博士认为，在这两种激素-行为系统中，北极筑巢鸟类的内分泌反应对环境刺激的敏感性会降低，从而延长了繁殖的机会。本研究项目所研究的内分泌适应性可能阐明极地动物避免延迟和/或冲突行为的生理机制，这些行为可能会降低它们成功繁殖的机会。

Little is understood of how environmental and social factors, particularly territorial aggression, affect the breeding of migratory arctic birds. Relationships between reproduction and environmental induced stress, where they play an important adaptive role, are virtually unknown in high latitude species. Many species arrive in the arctic,establish territories and eventually feed their nestlings in a fraction of the time for temperate birds. Adherence to this rigorous schedule, pairs must ignore environmental conditions that would normally inhibit or delay breeding at temperate latitudes. Dr. Wingfield proposes that these constraints have been met by adaptations of the endocrine system in arctic birds. This study proposes to continue examining the relationship between two potentially antagonistic hormones: corticosterone, which directs behavior away from reproductive activities and towards survival activities and testosterone, which mediates the aggressive behavior associated with territoriality. In both hormone-behavior systems, Dr. Wingfield suggests that the endocrine responses of arctic-nesting birds will show decrease sensitivity to environmental stimuli, allowing more prolonged opportunities to breed. The endocrine adaptations to be investigated in this research program may elucidate physiological mechanisms by which polar animals avoid delays and/or conflicting behaviors which might reduce their chances for successful reproduction.