Male hummingbirds have repeatedly evolved sexually dimorphic tails that they use as ornaments during courtship. We examine how male ornament evolution is reflected in female morphology. Lande's two‐step model of the evolution of dimorphism predicts that γ (the genetic correlation between the sexes) causes trait elaboration to first evolve quickly in both sexes, then dimorphism evolves more slowly. On the hummingbird phylogeny, tail length does not fit this two‐step model; although hummingbirds repeatedly evolved ornamental, elongated tails, dimorphism evolves on the same phylogenetic branch as elongation, implying that γ quickly evolves to be low over phylogenetic timescales. Male “bee” hummingbirds have evolved diverse rectrix shapes that they use to produce sound. Female morphologies exhibit subtle, pervasive correlations with male morphology. No female‐adaptive hypotheses explain these correlations, since females do not also make sounds with their tail. Subtle shape similarity has arisen through the genetic correlation with males, and is subject to intralocus sexual conflict. Intralocus sexual conflict may produce increased phenotypic variation of female ornaments. Other evolutionary constraints on tail morphology include a developmental correlation between neighboring tail‐feathers, biasing tail elaboration to occur most often at the ends of the feather tract (rectrix 5 or 1) and not the middle.

中文翻译：

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两性蜂鸟尾饰进化过程中微妙而普遍的遗传相关性

雄性蜂鸟反复进化出两性异形的尾巴，它们在求偶期间用作装饰品。我们研究了男性装饰品进化如何反映在女性形态中。Lande 的二态进化的两步模型预测 γ（两性之间的遗传相关性）导致性状细化首先在两性中快速进化，然后二态性进化得更慢。在蜂鸟系统发育中，尾长不适合这个两步模型；尽管蜂鸟反复进化出具有观赏性的细长尾巴，但二态性在与伸长相同的系统发育分支上进化，这意味着 γ 在系统发育时间尺度上迅速进化为低水平。雄性“蜜蜂”蜂鸟进化出不同的直角形状，它们用来产生声音。女性形态表现出微妙，与男性形态的普遍相关性。没有女性适应性假设可以解释这些相关性，因为女性也不会用尾巴发出声音。通过与雄性的遗传相关性产生了微妙的形状相似性，并受到位点内性冲突的影响。Intralocus 性冲突可能会增加女性饰品的表型变异。尾巴形态的其他进化限制包括相邻尾羽之间的发育相关性，偏向尾细化最常发生在羽毛束的末端（直纹 5 或 1）而不是中间。Intralocus 性冲突可能会增加女性饰品的表型变异。尾巴形态的其他进化限制包括相邻尾羽之间的发育相关性，偏向尾细化最常发生在羽毛束的末端（直纹 5 或 1）而不是中间。Intralocus 性冲突可能会增加女性饰品的表型变异。尾巴形态的其他进化限制包括相邻尾羽之间的发育相关性，偏向尾细化最常发生在羽毛束的末端（直纹 5 或 1）而不是中间。