Data from: Different ornaments signal male health and MHC variation in two populations of a warbler

Male traits that signal health and vigor are used by females to choose better quality mates, but in some cases, the male trait selected by females differs among populations. Multiple male traits can be maintained through female mate choice if both traits are equally honest indicators of male quality, but tests of this prediction are rare. By choosing males based on such traits, females could gain direct benefits from males (assistance with parental care), but when females choose extra-pair mates based on these traits, females gain only male sperm, and potentially indirect genetic benefits for their offspring. In common yellowthroats (Geothylpis trichas) female choice of extra-pair mates targets two different plumage ornaments; the black mask in a Wisconsin population and the yellow bib in a New York population. Previously we found that the black mask in Wisconsin is related to greater MHC class II variation, which in turn signals better survival and disease resistance. In this study we examined the signaling function of the yellow bib in New York to test whether it signals the same aspects of male quality as the black mask in Wisconsin. As predicted, we found that the yellow bib in New York is most closely associated with MHC variation, which also signals survival and resistance to blood parasites. Thus, the ornament preferred by females differs between the two populations, but the different ornaments signal similar aspects of male health and genetic quality, specifically, information regarding MHC variation and potential indirect genetic benefits to females.

雌性会借助传递雄性健康与活力的特征来挑选优质配偶，但在部分种群中，雌性偏好选择的雄性特征存在种群间差异。若两类雄性特征均为雄性质量的可靠诚实指示信号，则雌性择偶偏好可同时维持多种雄性特征，但目前针对该推论的实证检验仍较为匮乏。雌性通过此类特征选择雄性，可直接获得雄性提供的抚育协助等好处；但若雌性选择配对外配偶时仅基于这些特征，则仅能获得雄性精子，并可能为后代获得间接遗传收益。本研究对象为黄喉地莺（Geothylpis trichas），其种群的配对外配偶选择偏好两种不同的羽毛装饰特征：威斯康星种群偏好黑色面罩，纽约种群偏好黄色胸斑。此前本团队的研究发现，威斯康星种群的黑色面罩与更高的主要组织相容性复合体II类（Major Histocompatibility Complex class II，MHC II）基因多样性相关，而后者恰恰预示着更强的生存能力与抗病性。本研究聚焦纽约种群的黄色胸斑，旨在验证其是否与威斯康星种群的黑色面罩一样，能够指示雄性的同类质量特征。正如研究预期，我们发现纽约种群的黄色胸斑与MHC II基因多样性高度相关，而该特征同样预示着更强的生存能力与血液寄生虫抗性。综上，两个种群的雌性偏好的装饰特征存在差异，但不同的装饰均传递了雄性健康与遗传质量的相似信息，具体而言，均指向MHC II基因多样性相关信息，并能为雌性带来潜在的间接遗传收益。