Cotton Samuel, Fowler Kevin, Pomiankowski Andrew
The Galton Laboratory, Department of Biology, University College London, 4 Stephenson Way, London, NW1 2HE, United Kingdom.
Evolution. 2004 May;58(5):1038-46. doi: 10.1111/j.0014-3820.2004.tb00437.x.
We used the stalk-eyed fly Cyrtodiopsis dalmanni to examine predictions made by condition-dependent handicap models of sexual selection. Condition was experimentally varied by manipulation of larval food availability. Cyrtodiopsis dalmanni is a highly dimorphic species exhibiting strong sexual selection, and the male sexual ornament (exaggerated eyespan) showed strong condition-dependent expression relative to the homologous trait in females and nonsexual traits. Male eyespan also showed a great increase in standardized variance under stress, unlike nonsexual traits. The inflated variance of the male ornament was primarily attributable to condition-dependent (but body-size-independent) increase in variance. Thus, evaluation of male eyespan allows females to gain additional information about male condition over and above that given by body size. These findings accord well with condition-dependent handicap models of sexual selection.
我们利用长眼蝇（Cyrtodiopsis dalmanni）来检验性选择的条件依赖型 handicap 模型所做出的预测。通过操纵幼虫食物可获得性来实验性地改变条件。长眼蝇是一种具有高度二态性的物种，表现出强烈的性选择，并且雄性性饰（夸张的眼距）相对于雌性的同源性状和非性性状表现出强烈的条件依赖型表达。与非性性状不同，雄性眼距在应激状态下的标准化方差也大幅增加。雄性饰的方差膨胀主要归因于条件依赖型（但与体型无关）的方差增加。因此，对雄性眼距的评估使雌性能够获得关于雄性条件的额外信息，这些信息超出了体型所提供的信息。这些发现与性选择的条件依赖型 handicap 模型非常吻合。
