Data from: Linking micro- and macroevolutionary perspectives to evaluate the role of Quaternary sea-level oscillations in island diversification

With shifts in island area, isolation, and cycles of island fusion-fission, the role of Quaternary sea-level oscillations as drivers of diversification is complex and not well understood. Here we conduct parallel comparisons of population and species divergence between two island areas of equivalent size that have been affected differently by sea-level oscillations, with the aim to understand the micro- and macroevolutionary dynamics associated with sea-level change. Using genome-wide datasets for a clade of seven Amphiacusta ground cricket species endemic to the Puerto Rico Bank (PRB), we found consistently deeper interspecific divergences and higher population differentiation across the unfragmented Western PRB, in comparison to the currently fragmented Eastern PRB that has experienced extreme changes in island area and connectivity during the Quaternary. We evaluate alternative hypotheses related to the microevolutionary processes (population splitting, extinction and merging) that regulate the frequency of completed speciation across the PRB. Our results suggest that under certain combinations of archipelago characteristics and taxon traits the repeated changes in island area and connectivity may create an opposite effect to the hypothesized “species pump” action of oscillating sea levels. Our study highlights how a microevolutionary perspective can complement current macroecological work on the Quaternary dynamics of island biodiversity.

随着岛屿面积、隔离程度的变迁，以及岛屿融合-分裂的周期性循环，第四纪（Quaternary）海平面波动作为物种分化驱动因子的作用机制复杂且尚未被充分阐释。本研究针对两个面积相当但受海平面波动影响程度迥异的岛礁区域，开展种群与物种分化的平行对比分析，旨在揭示与海平面变化相关的微观与宏观进化动力学规律。本研究以波多黎各岛礁（Puerto Rico Bank, PRB）特有的7种安菲阿库斯塔地蟋（Amphiacusta）演化支的全基因组数据集为研究材料，对比发现：与第四纪期间经历了岛屿面积与连通性剧烈变化、当前仍处于片段化状态的东部PRB相比，未发生片段化的西部PRB整体呈现出更深的种间分化水平与更高的种群分化程度。本研究还对调控PRB区域完整物种形成频率的微观进化过程（种群分裂、灭绝与融合）相关的多种备选假说进行了检验。研究结果表明，在群岛特征与类群特性的特定组合下，岛屿面积与连通性的反复变化，可能会产生与学界假设的“物种泵（species pump）”——即波动海平面的驱动作用——相反的效应。本研究凸显了微观进化视角可有效补充当前针对岛屿生物多样性第四纪动态的宏观生态学研究。