Data from: Limited by the roof of the world: mountain radiations of Apollo swallowtails controlled by diversity-dependence processes

Mountainous areas comprise a substantial part of the world species richness, but the evolutionary origins and diversification of this biodiversity remain elusive. Diversification may result from differences in clade age (longer time to diversify), net diversification rates (faster speciation rate), or carrying capacities (number of niches). The likelihood of these macroevolutionary scenarios was assessed for six clades of Apollo swallowtails (Parnassius) that diversified mainly in the Himalayan-Tibetan region. The analyses suggest that neither the clade age, nor the speciation rate could explain the mountain butterfly diversification. Instead diversity-dependence models were strongly supported for each group. Models further estimated clades’ carrying capacities that approximate the current number of species, indicating that diversity equilibrium is reached (or close to be). The results suggest that diversification of mountain butterflies was controlled by ecological limits, which governed the number of niches, and provide macroevolutionary justification for regarding mountains as islands.

山地系统构成了全球物种丰富度（species richness）的重要组成部分，但此类生物多样性的演化起源与物种分化机制至今仍悬而未决。物种分化进程可能源于三类因素的差异：支系（clade）起源时间（即分化时长）、净物种分化速率（net diversification rates，即更快的成种速率），以及生态容纳量（carrying capacity，即生态位（niche）数量）。本研究针对主要在喜马拉雅-青藏高原区域发生物种分化的6个阿波罗绢蝶（Parnassius）支系，对上述三类宏观演化（macroevolutionary）情景的可能性进行了评估。分析结果显示，支系起源时间与成种速率均无法解释山地蝴蝶的物种分化格局。反之，各支系均显著支持多样性依赖模型（diversity-dependence models）。模型进一步估算出各支系的生态容纳量与当前物种总数相近，表明其物种多样性已达到（或接近达到）平衡状态。本研究结果表明，山地蝴蝶的物种分化受生态位数量所决定的生态上限调控，同时也为"山地可视为岛屿"这一观点提供了宏观演化层面的理论依据。