Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Unit of Biology and Ecology of Fishes, Humboldt University of Berlin, Philippstr. 13, Haus 16, 10115, Berlin, Germany.
Institute of Biochemistry and Biology, Unit of Evolutionary Biology/Systematic Zoology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Haus 26, 14476, Potsdam, Germany.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2020 Jul;206(4):571-585. doi: 10.1007/s00359-020-01425-7. Epub 2020 May 28.
Hybridization is widespread in fish and constitutes an important mechanism in fish speciation. There is, however, little knowledge about hybridization in mormyrids. F1-interspecies hybrids between Campylomormyrus tamandua ♂ × C. compressirostris ♀ were investigated concerning: (1) fertility; (2) survival of F2-fish and (3) new gene combinations in the F2-generation concerning the structure of the electric organ and features of the electric organ discharge. These F1-hybrids achieved sexual maturity at about 12-13.5 cm total length. A breeding group comprising six males and 13 females spawned 28 times naturally proving these F1-fish to be fertile. On average 228 eggs were spawned, the average fertilization rate was 47.8%. Eggs started to hatch 70-72 h after fertilization, average hatching rate was 95.6%. Average mortality rate during embryonic development amounted to 2.3%. Average malformation rate during the free embryonic stage was 27.7%. Exogenous feeding started on day 11. In total, we raised 353 normally developed larvae all of which died consecutively, the oldest specimen reaching an age of 5 months. During survival, the activities of the larval and adult electric organs were recorded and the structure of the adult electric organ was investigated histologically.
杂交在鱼类中广泛存在，是鱼类物种形成的重要机制。然而，关于电鳗目鱼类的杂交情况知之甚少。我们对坎氏南美牙脂鲤♂×窄头南美牙脂鲤♀的 F1 种间杂交后代进行了以下研究：（1）杂交后代的育性；（2）F2 代幼鱼的存活率；（3）在 F2 代中电器官结构和放电特征方面的新基因组合。这些 F1 杂种在全长约 12-13.5 厘米时达到性成熟。一个由 6 条雄鱼和 13 条雌鱼组成的繁殖群体自然繁殖了 28 次，证明这些 F1 杂种具有育性。平均产卵 228 枚，平均受精率为 47.8%。受精后 70-72 小时开始孵化，平均孵化率为 95.6%。胚胎发育过程中的平均死亡率为 2.3%。自由胚胎阶段的平均畸形率为 27.7%。第 11 天开始进行外部喂养。总共我们饲养了 353 只正常发育的幼鱼，它们都相继死亡，最老的个体达到了 5 个月的年龄。在存活期间，记录了幼鱼和成鱼电器官的活动，并对成鱼电器官的结构进行了组织学研究。
