DISSERTATION RESEARCH: Functional Significance of Elaborate Plumage Characters when Expressed in both Sexes: A Case Study of the Turquoise-Browed Motmot (Eumomota superciliosa)

羽状特征在两性间表达的功能意义：以蓝眉白颈燕为例。Emlen - ProfessorTroy G.精心制作的羽毛通常存在于两性异形的鸟类中，被认为是性选择的产物。 当在男性和女性身上都发现这种现象时，这就出现了一个悖论，因为女性通常不会为了接近男性而竞争。 这种精巧的单形性状可能是自然选择对两性平等作用的产物，也可能是两性平等作用的相互性选择的产物。 后者可能发生在雄性和雌性都为获得配偶而竞争的情况下。本项目旨在测试极端鸟类羽毛精心制作的适应功能，当在每种性别中平等表达时。 重点物种是单形和辉煌的羽毛绿松石眉莫特（Coraciiformes：Momotidae：Eumomota superciliosa），在墨西哥尤卡坦半岛北方的殖民繁殖地繁殖。 这种社会性一夫一妻制的物种的雄性和雌性都有一些同样夸张的羽毛特征，最明显的是一个细长的尾巴，末端是大大的椭圆形球拍，延伸到身体下方。这项调查将解决是否精心制作的球拍尖尾巴功能作为一种性信号用于竞争的配偶，或者如果它的功能在自然选择驱动的功利背景下。 五个假设的功能，精心制作的羽毛将测试使用行为观察和实验操作。 从这项研究中收集的信息将增加科学知识的选择力，保持复杂的字符在单态物种。

Functional significance of elaborate plumage characters when expressed in both sexes: a case study of the turquoise-browed motmot (Eumomota superciliosa)Stephen T. Emlen - ProfessorTroy G. Murphy - Graduate StudentElaborate plumage is generally found in sexually dimorphic species of birds and is thought to be the product of sexual selection. When found in both males and females, this presents a paradox because females generally do not compete for access to males. Such elaborate, monomorphic characters may be products of natural selection acting equally on the sexes, or they may be products of mutual sexual selection acting equally on the sexes. The latter may occur in cases where both males and females compete for access to mates.This project is designed to test the adaptive function of extreme avian plumage elaboration when expressed equally in each sex. The focal species is the monomorphic and brilliantly plumed turquoise-browed motmot (Coraciiformes: Momotidae: Eumomota superciliosa) which breeds at colonial breeding grounds in Northern Yucatan, Mexico. Both males and females of this socially monogamous species have a number of equally exaggerated plumage characters, most notably of which is an elongate tail that terminates in large oval-shaped rackets that extend far below the body of the bird. This investigation will address whether the elaborate racket-tipped tail functions as a sexual signal used in competition for mates, or if it functions in a utilitarian context driven by natural selection. Five hypotheses for the function of the elaborate plumage will be tested using behavioral observations and experimental manipulations. Information gathered from this study will increase the scientific knowledge on the selective forces that maintain elaborate characters in monomorphic species.