Sutton T L, DeGabriel J L, Riegler M, Cook J M
Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia.
Heredity (Edinb). 2017 May;118(5):486-490. doi: 10.1038/hdy.2016.125. Epub 2017 Jan 11.
Molecular tools increasingly reveal cryptic lineages and species that were previously unnoticed by traditional taxonomy. The discovery of cryptic species in sympatry prompts the question of how they coexist in the apparent absence of ecological divergence. However, this assumes first that the molecular taxonomy used to identify cryptic lineages delimits species boundaries accurately. This issue is important, because many diversity studies rely heavily or solely on data from mitochondrial DNA sequences for species delimitation, and several factors may lead to poor identification of species boundaries. We used a multilocus population genetics approach to show that three mtDNA-defined cryptic lineages of the fig wasp Pleistodontes imperialis Saunders, which pollinate Port Jackson figs (Ficus rubiginosa) in north-eastern Australia, represent reproductively isolated species. These species coexist locally, with about 13% of figs (where mating occurs) containing wasps from two or three species. However, there was no evidence for gene flow between them. Confirmed cases of coexisting cryptic species provide excellent opportunities for future studies of the ecological and evolutionary forces shaping both species coexistence and fig/pollinator coevolution.
分子工具越来越多地揭示出传统分类学以前未注意到的隐秘谱系和物种。同域中隐秘物种的发现引发了这样一个问题：在明显缺乏生态分化的情况下它们是如何共存的。然而，这首先假定用于识别隐秘谱系的分子分类学能够准确界定物种界限。这个问题很重要，因为许多多样性研究严重依赖或仅依赖线粒体DNA序列数据进行物种界定，而且有几个因素可能导致物种界限识别不佳。我们采用多基因座群体遗传学方法来表明，在澳大利亚东北部为杰克逊港榕属植物（Ficus rubiginosa）授粉的榕小蜂帝王榕小蜂（Pleistodontes imperialis Saunders）的三个由线粒体DNA界定的隐秘谱系代表了生殖隔离的物种。这些物种在当地共存，约13%的榕果（交配发生的地方）含有来自两个或三个物种的榕小蜂。然而，没有证据表明它们之间存在基因流动。已确认的共存隐秘物种案例为未来研究塑造物种共存以及榕树/传粉者协同进化的生态和进化力量提供了绝佳机会。
