Data from: Reef fish hybridisation: lessons learnt from butterflyfishes (genus Chaetodon)

Natural hybridisation is widespread among coral reef fishes. However, the ecological promoters and evolutionary consequences of reef fish hybridisation have not been thoroughly evaluated. Butterflyfishes form a high number of hybrids and represent an appropriate group to investigate hybridisation in reef fishes. This study provides a rare test of terrestrially-derived hybridisation theory in the marine environment by examining hybridisation between Chaetodon trifasciatus and Chaetodon lunulatus at Christmas Island. Overlapping spatial and dietary ecologies enable heterospecific encounters. Non-assortative mating and local rarity of both parent species appear to permit heterospecific breeding pair formation. Microsatellite loci and mtDNA confirmed the status of hybrids, which displayed the lowest genetic diversity in the sample and used a reduced suite of resources, suggesting decreased adaptability. Maternal contribution to hybridisation was unidirectional, and no introgression was detected, suggesting limited, localised evolutionary consequences of hybridisation. Comparisons to other reef fish hybridisation studies revealed that different evolutionary consequences emerge, despite being promoted by similar factors, possibly due to the magnitude of genetic distance between hybridising species. This study highlights the need for further enquiry aimed at evaluating the importance and long-term consequences of reef fish hybridisation.

自然杂交（Natural hybridisation）在珊瑚礁鱼类中广泛存在。然而，礁栖鱼类杂交的生态驱动因子与演化后果尚未得到充分评估。蝴蝶鱼类（Butterflyfishes）可形成大量杂交种，是研究礁栖鱼类杂交的适宜类群。本研究以圣诞岛（Christmas Island）处的三带蝴蝶鱼（Chaetodon trifasciatus）与新月蝴蝶鱼（Chaetodon lunulatus）为研究对象，为海洋环境中的陆地起源杂交理论提供了罕见的实证检验。二者的空间与摄食生态位重叠为异种个体相遇创造了条件；非选型交配以及双亲种群的局部稀有性，似乎促成了异种繁殖配对的形成。微卫星位点（microsatellite loci）与线粒体DNA（mtDNA）验证了杂交个体的物种身份，这类个体在样本中展现出最低的遗传多样性，且资源利用范围显著缩减，这暗示其适应性有所下降。杂交的母系贡献具有单向性，且未检测到基因渐渗现象，表明此次杂交仅带来了有限的局域演化后果。对比其他礁栖鱼类杂交研究可见，尽管杂交受到相似生态因子的驱动，不同研究却呈现出迥异的演化后果，这可能源于杂交物种间遗传距离的差异。本研究凸显了开展更多系统性探究的必要性，以全面评估礁栖鱼类杂交的重要性及其长期演化后果。