Visual processes in African cichlid fishes

东非大裂谷湖泊中的慈鲷为研究性选择提供了一个极好的自然实验室。马拉维湖有1000多种特有物种，它们在营养适应和行为方面有着惊人的多样性。适应性辐射的例子之所以如此令人兴奋，是因为它是在非常短的时间内进化出来的。关键的行为决定，如择偶，会深刻影响个体的健康。性选择在很大程度上依赖于视觉线索，这些线索必须迅速转化为适当的行为，最终使适应性最大化。雌性慈鲷能够通过身体颜色和其他可能的视觉线索，在视觉上区分自己物种和近亲物种的雄性。在同域非生态分化的情况下，基于种内颜色信号的配偶选择在维持物种多样性中起着至关重要的作用。此外，这些慈鲷在时间和空间动态光环境中成功选择配偶需要敏锐的视觉辨别能力。因此，颜色在慈鲷中的作用被认为是非洲大湖慈鲷多样化的核心，然而我们对身体颜色和偏振模式的基础以及慈鲷视觉系统的功能特征的理解仍然相当有限。

Cichlid fishes in the East African Rift Valley lakes provide an excellent natural laboratory for the study of sexual selection. Lake Malawi has more than 1,000 endemic species with a striking diversity in trophic adaptations and behaviours. What makes this example of adaptive radiation so exciting is that it evolved in a notably short time. Critical behavioural decisions such as choosing a mate profoundly affect an individual's fitness. Sexual selection can depend heavily on visual cues that must be rapidly translated into appropriate behavioural actions that eventually maximize fitness. Female cichlids are able to visually discriminate between males of their own species and closely related species, using body color and possibly other visual cues. Mate choice based on intraspecific color signaling plays a critical role in maintaining biodiversity when species are sympatric and not ecologically differentiated. Furthermore, successful mate choice in these cichlids necessitates acute visual discrimination in a temporally and spatially dynamic light environment. The role of color in cichlids is thus considered central to cichlid diversification in the great lakes of Africa, yet our understanding of the basis for body color and polarization patterns and the functional characteristics of cichlid visual systems remain quite limited.