Greene E, Lyon B E, Muehter V R, Ratcliffe L, Oliver S J, Boag P T
Division of Biological Sciences, The University of Montana, Missoula 59812, USA.
Nature. 2000 Oct 26;407(6807):1000-3. doi: 10.1038/35039500.
The theory of sexual selection was developed to explain the evolution of highly exaggerated sexual ornaments. Now supported by vast empirical evidence, sexual selection is generally considered to favour individuals with the most extreme trait expression. Here we describe disruptive selection on a sexual ornament, plumage coloration, in yearling male lazuli buntings (Passerina amoena). In habitats with limited good-quality nesting cover, the dullest and the brightest yearlings were more successful in obtaining high-quality territories, pairing with females and siring offspring, than yearlings with intermediate plumage. This pattern reflects the way that territorial adult males vary levels of aggression to influence the structure of their social neighbourhood. Adult males showed less aggression towards dull yearlings than intermediate and bright ones, permitting the dull yearlings to settle on good territories nearby. Fitness comparisons based on paternity analyses showed that both the adults and dull yearlings benefited genetically from this arrangement, revealing a rare example of sexually selected male-male cooperation.
性选择理论的提出是为了解释高度夸张的性装饰的进化。如今，性选择得到了大量实证证据的支持，通常被认为有利于具有最极端性状表达的个体。在此，我们描述了一岁雄性蓝翅雀（Passerina amoena）的一种性装饰——羽毛颜色上的分裂选择。在优质筑巢掩体有限的栖息地中，最 dull 和最亮的一岁鸟比羽毛处于中间状态的一岁鸟在获得优质领地、与雌性交配并繁衍后代方面更为成功。这种模式反映了成年领地雄性改变攻击水平以影响其社会邻域结构的方式。成年雄性对 dull 的一岁鸟表现出的攻击性低于对处于中间状态和亮色的一岁鸟，从而使 dull 的一岁鸟能够在附近的优质领地定居。基于亲权分析的适合度比较表明，成年鸟和 dull 的一岁鸟都从这种安排中获得了遗传益处，揭示了一个罕见的性选择的雄雄合作实例。 （注：原文中“dullest”和“dull”在中文里较难找到完全对应的精准词汇，暂用“dull”翻译为“ dull 的”，可根据实际情况优化）
