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 (Geothlypis 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.雌性会借助传递健康与活力信号的雄性性状，遴选品质更优良的配偶；但在部分种群中，雌性偏好的雄性性状存在差异。若两种雄性性状均可如实反映雄性个体质量，则可通过雌性配偶选择维持多种雄性性状，不过针对这一理论预测的实证研究仍较为少见。雌性通过此类性状选择雄性，可从雄性处获得直接收益（如育雏协助）；但若雌性基于这些性状选择婚外配偶，则仅能获取雄性精子，并可能为后代获得间接遗传收益。在黄喉地莺（Geothlypis trichas）中，雌性对婚外配偶的选择偏好两种不同的羽饰装饰：威斯康星种群的黑色面罩，以及纽约种群的黄色胸斑。此前我们的研究发现，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（Major Histocompatibility Complex, MHC）Ⅱ类基因多样性呈正相关，而该特征本身即可预示更强的生存能力与疾病抗性。本研究针对纽约种群的黄色胸斑的信号功能展开探究，以验证其是否与威斯康星种群的黑色面罩传递相同的雄性质量相关信息。正如理论预测所示，我们发现纽约种群的黄色胸斑与MHC基因多样性的关联最为紧密，而该特征同样预示了更强的生存能力与血液寄生虫抗性。由此可见，两个种群的雌性所偏好的装饰性状存在差异，但这些不同的装饰均传递了相似的雄性健康与遗传质量信息，具体而言，即关于MHC基因多样性的信息，以及可为雌性带来的潜在间接遗传收益。