Predicting speciation is a fundamental goal of research in evolutionary ecology. The probability of speciation is often positively correlated with ecosystem size. Although the mechanisms driving this correlation are generally difficult to identify, a shared geographical and ecological context provides a suitable condition to study the mechanisms that promote speciation in large ecosystems by reducing the number of factors to be considered. Here, we determined the correlation between speciation and ecosystem size, and discuss the underlying mechanisms of this relationship, using a probable parallel ecotype formation for freshwater fish. Our population genetic analysis revealed that speciation of the landlocked goby, Rhinogobius sp. YB, of the Ryukyu Archipelago, Japan, from its migratory ancestor, R. brunneus, occurred in parallel across five islands. Logistic regression analysis showed that speciation probability could be predicted using island size. The results suggest that ecosystem size predicts the occurrence of adaptation and reproductive isolation, probably through its association with three possible factors: divergent selection strength, population persistence, and occurrence probability of habitat separation.

中文翻译：

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生态系统的大小预测了迁徙淡水鱼形成物种的可能性。

预测物种形成是进化生态学研究的基本目标。物种形成的可能性通常与生态系统的大小呈正相关。尽管通常很难确定驱动这种相关性的机制，但是共享的地理和生态环境为研究通过减少要考虑的因素数量而促进大型生态系统中的物种形成的机制提供了合适的条件。在这里，我们确定了物种形成与生态系统大小之间的相关性，并使用淡水鱼的可能平行生态型形成，讨论了这种关系的潜在机制。我们的人口遗传分析表明，内陆虾虎鱼Rhinogobius sp。的物种形成。YB，日本琉球群岛的祖先，R. brunneus平行发生在五个岛屿上。Logistic回归分析表明，可以使用岛屿大小来预测物种形成概率。结果表明，生态系统的大小可能通过与三个可能的因素相关联来预测适应和生殖隔离的发生：选择强度的差异，种群的持久性以及生境分离的发生概率。