Collaborative Research: Hormones and Avian Sociality

这个项目的目标是了解社会行为的荷尔蒙基础，特别是鸟类的攻击性和亲代行为。这项研究将集中在两种关系密切的松鸦身上，它们生活在亚利桑那州，彼此距离很近，但社会制度却截然不同。这项合作研究工作将把杰拉姆·布朗博士对墨西哥松鸦的长期研究（超过20年）与卡罗尔·弗莱克博士对松鸦个体表现出不同行为的荷尔蒙基础的研究结合起来。在这项研究中，大量彩色条纹鸟类的谱系和繁殖历史是已知的。特别令人感兴趣的是：(1)墨西哥松鸦允许许多个体在一个社会群体中共存的机制，而灌木丛松鸦则不允许；(2)促进非繁殖墨西哥松鸦父母式（帮助）行为的机制（例如，为什么这些鸟帮助抚养其他鸟的后代，而不是自己繁殖）。研究将集中在睾酮和催乳素上，前者在其他物种中对控制个体之间的攻击性和性行为都很重要，后者对促进鸟类的亲代行为很重要。通过将小血液样本中的激素水平与鸟类的行为联系起来，并通过改变自由生活的个体的激素水平。Vleck和Brown将测试以下假设：(1)高水平的催乳素是父母和帮助行为的原因；(2)群体生活是由睾丸激素水平的普遍下降所促进的。这项研究将揭示同一物种内个体生殖行为差异的激素基础，也将为不同物种中非常多样化的社会组织的激素基础提供信息。

The goal of this project is to understand the hormonal basis of social behavior, particularly aggressive and parental behavior in birds. The research will focus on two closely related species of jays that live in close proximity to each other in Arizona but have very different social systems. This collaborative research effort will bring together Dr. Jerram Brown's long-term (more than 20-year) study of Mexican jays, in which the genealogies and breeding history of a large number of color-banded birds are known, with a study by Dr. Carol Vleck on the hormonal basis for the different behaviors that individual jays exhibit. Of particular interest are (1) the mechanisms that permit co-existence of many individuals within a social group in Mexican jays but not in scrub jays and (2) the mechanisms that promote parental-like (helping) behavior in non-breeding Mexican jays (e.g., why these birds help raise the young of others rather than breeding themselves). The research will concentrate on testosterone, which in other species is important in controlling both aggressive and sexual interactions between individuals, and on prolactin, which is important in promoting parental behavior in birds. By correlating hormone levels in small blood samples with the behavior of the birds, and by altering the levels of these hormones in free-living individuals, Drs. Vleck and Brown will test the hypotheses that (1) high levels of prolactin are responsible for both parental and helping behavior and that (2) group living is promoted by a general decrease in testosterone levels. This study will shed light on the hormonal basis for the differences in reproductive behaviors of individuals within one species and will also provide information on the hormonal bases of very diverse social organizations in different species.