Postzygote isolation is an important part of species isolation, especially for fish, and it can be divided into two aspects: genetic isolation and ecological isolation. With the increase in parental genetic distance, the intensity of genetic isolation between them also increases. Will the increase in parental ecological niche differences also lead to the increase in ecological isolation intensity between them? This question is difficult to answer based on the current literature due to the lack of hybridization cases of contrasting ecological niche parents. Cyprinid fish parents (Schizothorax wangchiachii and Percocypris pingi) with contrasting ecological niches (herbivorous and carnivorous) and their F1 hybrids were used as research objects. Fish and periphytic algae were selected as food corresponding to different parental resources. The foraging-related traits of these hybrids are generally the same between parents; however, the intermediate foraging traits of hybrids did not result in intermediate foraging performance for parental resources, and these hybrids could hardly forage for parental resources. The poor foraging performance of these hybrids for parental resources was caused not only by the decline in the foraging ability of these hybrids but, more importantly, by the decrease in foraging activity. Interestingly, these hybrids initially showed a high interest in foraging small fishes; however, after the first successful capture, these hybrids had difficulty ingesting fish and spit them out, which led to the subsequent decrease in foraging activity. We designed a series of experiments to explore the mechanism of the fish spitting of these hybrids, excluding the taste and the size of prey, and found that the decrease in their pharyngeal tooth puncture ability may be the reason. This study was the first to demonstrate that these parents with contrasting ecological niches will produce great postzygotic ecological isolation for parental resources. The poor foraging performance of these hybrids for parental resources is mainly due to the decrease in foraging activity. Interestingly, these hybrids have obvious fish-spitting behaviour, which is a typical example of the incompatibility between intermediate traits and genetic behaviors.

中文翻译：

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不同的生态位会导致巨大的合子后生态隔离：食肉和草食鲤科鱼类之间的杂交案例

后合子分离是物种分离的重要部分，特别是对于鱼类，它可以分为两个方面：遗传分离和生态分离。随着父母遗传距离的增加，它们之间的遗传隔离强度也增加了。父母生态位差异的增加还会导致父母之间生态隔离强度的增加吗？根据目前的文献，由于缺乏生态位亲本对比的杂交案例，这个问题很难回答。研究对象为具有相对生态位（食性和肉食性）的鲤鱼亲鱼（Schizothorax wangchiachii和Percocypris pingi）及其F1杂种。鱼类和附生藻类被选为与父母资源不同相对应的食物。这些杂种的觅食相关性状在父母之间通常是相同的。然而，杂种的中间觅食性状并未导致亲本资源的中等觅食性能，并且这些杂种很难为亲本资源觅食。这些杂种对亲本资源的觅食性能差，不仅是由于这些杂种的觅食能力下降，而且更重要的是，由于觅食活动的减少。有趣的是，这些杂种最初对觅食小鱼表现出很高的兴趣。然而，在第一次成功捕获后，这些杂种很难摄取鱼并将其吐出，这导致随后的觅食活动减少。我们设计了一系列实验来探索这些杂种鱼吐痰的机制，排除猎物的味道和大小，发现其咽齿穿刺能力下降可能是原因。这项研究首次证明了这些具有相对生态位优势的父母将为父母资源产生巨大的合子后生态隔离。这些杂种对亲本资源的觅食性能差主要是由于觅食活动的减少。有趣的是，这些杂种具有明显的吐鱼行为，这是中间性状与遗传行为之间不相容的典型例子。这项研究首次证明了这些具有相对生态位优势的父母将为父母资源产生巨大的合子后生态隔离。这些杂种对亲本资源的觅食性能差主要是由于觅食活动的减少。有趣的是，这些杂种具有明显的吐鱼行为，这是中间性状与遗传行为之间不相容的典型例子。这项研究首次证明了这些具有相对生态位优势的父母将为父母资源产生巨大的合子后生态隔离。这些杂种对亲本资源的觅食性能差主要是由于觅食活动的减少。有趣的是，这些杂种具有明显的吐鱼行为，这是中间性状与遗传行为之间不相容的典型例子。