Data from: Testosterone activates sexual dimorphism including male-typical carotenoid but not melanin plumage pigmentation in a female bird

In males it is frequently testosterone (T) that activates the expression of sexually selected morphological and behavioral displays, but the role of T in regulating similar traits in females is less clear. Here we combine correlational data with results from T and gonadotropin-releasing hormone (GnRH) manipulations in both sexes to assess the role of T in mediating sexually dimorphic coloration and morphology in the red-backed fairy-wren (Malurus melanocephalus). We show that (1) natural variation in female expression of ornamental traits (darkened bills and red back feathers) are positively associated with age and circulating androgen titres, (2) females have the capacity to express most male-typical traits in response to exogenous T, including carotenoid-pigmented body plumage, shorter feathers, darkened bill, and enlarged cloacal protuberance, but (3) appear constrained in production of male-typical melanin-pigmented plumage, and (4) low androgen levels during the pre-nuptial molt, probably due to low ovarian capacity for steroid production (or LH-sensitivity), prevent females from developing male-like ornamentation. Thus, females appear to retain molecular mechanism for hormonally regulated male-typical ornamentation, although these are rarely activated because of insufficient production of the hormonal signal.

在雄性个体中，睾酮（testosterone, T）通常会激活性选择所塑造的形态与行为展示性状的表达，但睾酮在雌性同类性状调控中所发挥的作用仍不甚明确。本研究结合相关性数据，以及对雌雄个体施加睾酮与促性腺激素释放激素（gonadotropin-releasing hormone, GnRH）干预后的实验结果，以评估睾酮在调控红背细尾鹩莺（Malurus melanocephalus）性二态性体色与形态性状中的作用。研究结果显示：（1）雌性装饰性性状（黑化喙部与红色背羽）的自然表达变异与年龄及循环雄激素滴度呈显著正相关；（2）雌性在施加外源性睾酮后，能够表达多数雄性典型性状，包括类胡萝卜素着色的体羽、更短的羽毛、黑化喙部以及膨大的泄殖腔突起；（3）但雌性在产生雄性典型的黑色素着色羽毛时存在表达限制；（4）繁殖前换羽期的低雄激素水平（可能源于卵巢类固醇生成能力（或促黄体素敏感性）低下）会阻碍雌性发育出雄性样的装饰性状。综上，尽管因激素信号生成不足而极少被激活，但雌性仍保留了受激素调控的雄性典型装饰性状的分子机制。