Department of Ecology and Evolutionary Biology, University of Colorado , Boulder, CO 80302 , USA.
Philos Trans R Soc Lond B Biol Sci. 2019 Apr 1;374(1769):20180205. doi: 10.1098/rstb.2018.0205.
The cuckoo catfish, Synodontis multipunctatus, is the only known obligate brood parasite among fishes, exploiting the parental care of mouthbrooding cichlids endemic to Lake Tanganyika. Comparisons of this system to brood parasitism in birds may reveal broader principles that underlie the evolution of this life-history strategy in vertebrates. However, little is known about the features of the cuckoo catfish that enable this species to successfully parasitize cichlids. Here, we examine early ontogeny of the cuckoo catfish and compare it to that of its cichlid hosts as well as a non-parasitic congener. We found that cuckoo catfish embryos develop and hatch in advance of host embryos, and begin feeding on cichlid young just as they start to hatch. Overall timing of ontogeny in the cuckoo catfish was found to be similar to that of the substrate-spawning congener Synodontis lucipinnis, suggesting that more rapid development of the cuckoo catfish relative to cichlids is not a unique adaptation to brood parasitism. However, we found that cuckoo catfish progeny exhibit extensive morphological differences from S. lucipinnis, which may represent adaptations to brood parasitism. These life-history observations reveal both similarities and differences between the cuckoo catfish system and brood parasitism in other lineages. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.
非洲锯齿鲇，Synodontis multipunctatus，是鱼类中唯一已知的专性寄生种，它利用坦干伊喀湖特有的口孵慈鲷的亲代抚育来寄生。将这个系统与鸟类的寄生行为进行比较，可能会揭示出脊椎动物这种生活史策略进化背后更广泛的原则。然而，对于这种寄生行为使这种鱼能够成功寄生慈鲷的特征，我们知之甚少。在这里，我们研究了非洲锯齿鲇的早期发育，并将其与宿主慈鲷以及非寄生的同类进行了比较。我们发现，非洲锯齿鲇的胚胎比宿主的胚胎更早发育和孵化，并在慈鲷幼鱼开始孵化时就开始以它们为食。非洲锯齿鲇的整体发育时间与基质产卵的同类 Synodontis lucipinnis 相似，这表明非洲锯齿鲇相对于慈鲷更快的发育并不是其对寄生行为的独特适应。然而，我们发现非洲锯齿鲇的后代与 S. lucipinnis 表现出广泛的形态差异，这可能代表了对寄生行为的适应。这些生活史观察揭示了非洲锯齿鲇系统与其他谱系中的寄生行为之间的相似之处和不同之处。本文是主题为“寄生生物学的协同进化：从机制到模式”的一部分。
