Adaptive radiation, speciation, and reproductive isolation in African weakly electric fishes (genus Campylomormyrus, Mormyridae, Teleostei)

非洲特有的孔鱼构成了世界上最大的电鱼种群。它们的电子器官放电(EOD)是年龄、性别和物种特有的。我们的目的是评估EOD的差异是否在物种形成过程中作为前合子隔离机制发挥关键作用。然后，我们假设EOD在形态和遗传上相似的物种中应该是特别不同的。我们选择Camylomormyus Numenius物种复合体作为模式分类群，是因为它包含了数量尚不清楚的形态相似的物种，它们的EOD具有显著的差异。我们将结合分子分析(线粒体Cytb基因，几个非连锁的核基因)和电生理学(与性别、年龄、形态类型和基因有关的电子器官放电)。EOD对于物种特定配偶识别的意义将在配偶选择实验中进行评估。在我们的前期工作中，我们(1)开发了必要的分子标记，(2)建立了EOD评估，(3)优化了弯曲肌活标本的实验室维护。该项目的最终目标是更好地了解微弱电力与非洲电鱼辐射的相关性。

The endemic African mormyrids comprise the single largest group of electric fishes worldwide. Their electric organ discharge (EOD) is age, sex, and species specific. We aim at evaluating whether differences in EOD play a key role as prezygotic isolation mechanisms during speciation. Then, we hypothesize that EODs should be particularily divergent among morphologically and genetically similar species. We chose the Campylomormyrus numenius species complex as a model taxon because it contains a still unknown number of morphologically similar species with strikingly divergent EODs. We will combine molecular analysis (mitochondrial cyt b gene, several unlinked nuclear loci) with electrophysiology (electric organ discharge in relation to sex, age, morphotype, and genotype). The significance of EODs for species specific mate recognition will be assessed in mate choice experiments. During our preliminary work, we (1) develped the necessary molecular markers, (2) established the EOD assessment, and (3) optimized the laboratory maintenance of live Campylomormyrus specimens. The ultimate goal of this project is to better understand the relevance of weak electricity in the radiation of African electric fish.