Reproduction, Territoriality and Hormones in a Rainforest Bird Model System

雨林鸟类模型系统中的繁殖、领地性和激素

• 批准号: 9983571
• 负责人: Michaela Hau
• 金额: $ 27.88万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-15 至 2001-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9983571&HistoricalAwards=false
• 关键词: Reproduction; Territoriality; Hormones; Rainforest; Bird

In strongly seasonal environments, such as in mid and high latitudes, most bird species reproduce during short periods in spring and summer only. During this time, these species also aggressively defend territories. Reproductive activity is stimulated by increasing daylength in spring, which also initiates secretion of reproductive hormones like testosterone to regulate reproductive and territorial behavior. Our understanding of the environmental cues and the hormonal mechanisms controlling reproduction and territoriality in birds comes almost entirely from studies on temperate zone species. However, the majority of bird species live at tropical latitudes, yet for these we have only vague ideas of how they adjust these processes on a seasonal basis. In contrast to most temperate birds, many tropical birds have adopted long breeding seasons and maintenance of permanent territories. Here the Spotted Antbird (Hylophylax naevioides) from the rainforest in Panama will be used as a new model species for tropical endocrinology, to conduct an in-detail investigation of the mechanisms that regulate reproduction and territoriality in tropical birds. Previous work has revealed an unusually high sensitivity to small daylength changes in these birds, which may allow this species to use photoperiod as a seasonal signal in their tropical environment. Experimental manipulations on captive Spotted Antbirds will allow to elucidate the mechanism for such photoperiodic sensitivity and also show the importance of food cues for timing of breeding. Like many other tropical birds Spotted Antbirds can have very low levels of testosterone throughout the year, despite aggressively defending territories. Field and laboratory experiments in which testosterone levels and actions are manipulated will clarify the mechanism that controls aggressive territorial behavior year-round. These experiments will test the validity of endocrine models developed for temperate zone birds. This project will greatly advance our understanding of whether tropical species rely on similar seasonal and endocrine systems as temperate zone birds or whether they have evolved different physiological solutions to cope with their environment. Because tropical rainforests are disappearing at an alarming rate, detailed knowledge of reproductive mechanisms will provide critical baseline information for potentially threatened species.

在强烈的季节性环境中，例如中纬度和高纬度地区，大多数鸟类仅在春季和夏季的短时间内繁殖。在此期间，这些物种也积极捍卫领土。生殖活性通过春季的日长度增加而刺激，这也引发了睾丸激素（如睾丸激素）的分泌，以调节生殖和领土行为。我们对控制鸟类繁殖和领土的环境线索以及荷尔蒙机制的理解几乎完全来自对温带物种的研究。但是，大多数鸟类都生活在热带纬度上，但是对于这些鸟类，我们只对它们如何按季节性调整这些过程有模糊的想法。与大多数温带鸟类相反，许多热带鸟类采用了长期的繁殖季节和永久性领土的维护。在这里，来自巴拿马雨林的斑点蚂蚁（Hylophylax naevioides）将用作热带内分泌学的新模型物种，以对调节热带鸟类的繁​​殖和领土的机制进行详细研究。先前的工作表明，这些鸟类的小日长度变化具有异常高的敏感性，这可能会使该物种在其热带环境中使用光周期作为季节性信号。对圈养的斑点进行的实验操作将允许阐明这种光周期灵敏度的机制，并显示食物提示对于育种时机的重要性。像许多其他热带鸟类一样，尽管捍卫领土，但全年睾丸激素的水平可能很低。操纵睾丸激素水平和作用的现场和实验室实验将阐明全年控制攻击性领土行为的机制。这些实验将测试为温带鸟类开发的内分泌模型的有效性。该项目将大大提高我们对热带物种是否依赖于温带鸟类的季节性和内分泌系统，或者它们是否发展了不同的生理解决方案以应对环境。由于热带雨林正在以惊人的速度消失，因此对生殖机制的详细知识将为潜在受威胁的物种提供关键的基线信息。