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父母行为。这项研究将集中在亚利桑那州两种关系密切的松鸦身上，这两种松鸦生活在非常接近的地方，但社会制度却截然不同。这项合作研究工作将结合Jerram Brown博士对墨西哥鸟的长期(20多年)研究，其中已知大量彩带鸟类的系谱和繁殖史，Carol Vleck博士将对个别Jay表现出的不同行为进行荷尔蒙基础研究。特别令人感兴趣的是(1)允许许多个体在一个社会群体中共存的机制，而不是在灌木鸟中共存的机制；(2)在非繁殖的墨西哥鸦中促进类似父母(帮助)行为的机制(例如，为什么这些鸟帮助抚养他人的后代，而不是自己繁殖)。这项研究将集中在睾酮和催乳素上，睾丸激素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，催乳素在促进鸟类父母的行为方面也很重要。通过将少量血液样本中的荷尔蒙水平与鸟类的行为相关联，并通过改变自由生活个体中这些荷尔蒙的水平，弗莱克和布朗博士将检验以下假设：(1)高水平的催乳素对父母和帮助行为都负有责任，(2)睾酮水平的普遍下降促进了群体生活。这项研究将阐明一个物种内个体生殖行为差异的荷尔蒙基础，也将提供不同物种中非常不同的社会组织的荷尔蒙基础的信息。

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.