Leys Marie, Keller Irene, Robinson Christopher T, Räsänen Katja
Department of Aquatic Ecology, EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600, Dübendorf, Switzerland.
Institute of Integrative Biology, ETH-Zurich, 8092, Zurich, Switzerland.
Mol Ecol. 2017 Mar;26(6):1670-1686. doi: 10.1111/mec.14026. Epub 2017 Feb 6.
Understanding ecological divergence of morphologically similar but genetically distinct species - previously considered as a single morphospecies - is of key importance in evolutionary ecology and conservation biology. Despite their morphological similarity, cryptic species may have evolved distinct adaptations. If such ecological divergence is unaccounted for, any predictions about their responses to environmental change and biodiversity loss may be biased. We used spatio-temporally replicated field surveys of larval cohort structure and population genetic analyses (using nuclear microsatellite markers) to test for life-history divergence between two cryptic lineages of the alpine mayfly Baetis alpinus in the Swiss Alps. We found that the more widespread and abundant cryptic lineage represents a 'generalist' with at least two cohorts per year, whereas the less abundant lineage is restricted to higher elevations and represents a 'specialist' with a single cohort per year. Importantly, our results indicate partial temporal segregation in reproductive periods between these lineages, potentially facilitating local coexistence and reproductive isolation. Taken together, our findings emphasize the need for a taxonomic revision: widespread and apparently generalist morphospecies can hide cryptic lineages with much narrower ecological niches and distribution ranges.
理解形态相似但基因不同的物种（以前被视为单一形态物种）的生态分化，在进化生态学和保护生物学中至关重要。尽管隐性物种形态相似，但它们可能已经进化出了不同的适应性。如果这种生态分化未被考虑在内，那么任何关于它们对环境变化和生物多样性丧失反应的预测可能都会有偏差。我们利用幼虫群体结构的时空重复实地调查和群体遗传分析（使用核微卫星标记），来测试瑞士阿尔卑斯山高山蜉蝣Baetis alpinus两个隐性谱系之间的生活史分化。我们发现，分布更广且数量更多的隐性谱系代表一种“广适种”，每年至少有两个群体，而数量较少的谱系局限于更高海拔地区，代表一种“特化种”，每年只有一个群体。重要的是，我们的结果表明这些谱系在繁殖期存在部分时间隔离，这可能有助于它们在当地共存和生殖隔离。综上所述，我们的研究结果强调了进行分类学修订的必要性：广泛分布且看似广适的形态物种可能隐藏着生态位和分布范围窄得多的隐性谱系。
