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

精致的羽毛特征在两性中表达时的功能意义：以绿松石眉座右铭(Eumomota Superciliosa)Stephen T.Emlen-教授Troy G.Murphy-研究生的羽毛为例通常在两性鸟类中发现，被认为是性别选择的产物。当在男性和女性身上都发现这一点时，这是一个悖论，因为女性通常不会竞争获得男性的机会。这种精致的、单态的角色可能是自然选择平等作用于性别的产物，也可能是相互性别选择平等作用的产物。后一种情况可能发生在雄性和雌性都竞争交配的情况下。这个项目旨在测试极端的禽类羽毛精加工在两性平等表达时的适应功能。重点物种是在墨西哥尤卡坦北部殖民地繁殖地繁殖的单形性和羽毛鲜艳的绿松石眉护语(喙形目：莫莫蒂科：顶冠足目Eumomota Superciliosa)。这种社会性一夫一妻制物种的雄性和雌性都有许多同样夸张的羽毛特征，其中最引人注目的是一条细长的尾巴，尾巴末端是巨大的椭圆形球拍，远远延伸到鸟的身体下方。这项调查将解决精心制作的球拍尖端的尾巴是否在争夺配偶时作为性信号发挥作用，或者它是否在自然选择驱动的功利性背景下发挥作用。关于这种精致羽毛功能的五种假设将通过行为观察和实验操作进行验证。从这项研究中收集的信息将增加关于保持单态物种精致特征的选择性力量的科学知识。

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.