In sexually dimorphic species characterized by exaggerated male ornamentation, behavioral isolation is often attributed to female preferences for conspecific male signals. Yet, in a number of sexually dimorphic species, male mate choice also results in behavioral isolation. In many of these cases, the female traits that mediate species boundaries are unclear. Females in sexually dimorphic species typically lack many of the elaborate traits that are present in males and that are often used for taxonomic classification of species. In a diverse and largely sexually dimorphic group of fishes called darters (Percidae: Etheostoma), male mate choice contributes to behavioral isolation between a number of species; however, studies addressing which female traits males prefer are lacking. In the current study, we identified the dominant female pattern for two sympatric species, Etheostoma zonale and E. barrenense, using pattern energy analysis, and we used discriminate function analysis to identify which aspects of female patterning can reliably classify species. We then tested the role of female features in male mate choice for E. zonale, by measuring male preference for computer animations displaying the identified (species-specific) conspecific features. We found that the region above the lateral line is important in mediating male mate preferences, with males spending a significantly greater proportion of time with animations exhibiting conspecific female patterning in this region than with animations exhibiting heterospecific female patterning. Our results suggest that the aspects of female phenotypes that are the target of male mate choice are different from the conspicuous male phenotypes that traditionally characterize species.

中文翻译：

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识别女性表型，该表型促进有性双态鱼的行为隔离（Etheostoma zonale）

在以夸张的雄性装饰为特征的性二态物种中，行为隔离通常归因于雌性对同种雄性信号的偏爱。然而，在许多有性双态物种中，雄性配偶的选择也导致行为孤立。在许多情况下，尚不清楚介导物种边界的雌性特性。有性双态物种中的雌性通常缺乏雄性中存在的许多复杂特征，这些特征通常用于物种的分类学分类。在多种多样且很大程度上具有性别异形的鱼类中，它们被称为飞鱼（Percidae：Etheostoma），雄性伴侣的选择有助于许多物种之间的行为隔离；但是，缺乏针对男性偏爱女性特征的研究。在当前的研究中，我们使用模式能量分析确定了两种同养物种占主导地位的雌性模式（Etheostoma zonale和E. barrenense），并使用区分函数分析来确定女性模式的哪些方面可以可靠地对物种进行分类。然后，我们测试了女性特征在E. zonale的男性伴侣选择中的作用，通过测量男性对显示已识别（特定物种）特定特征的计算机动画的偏好。我们发现，横向线上方的区域对于调解男性配偶的喜好很重要，在这个区域，雄性花的时间显示同种雌性图案的动画要比显出异种雌性的动画花费更多的时间。我们的结果表明，作为男性伴侣选择目标的女性表型方面与传统上表征物种的明显男性表型不同。