Gómez J M, Muñoz-Pajares A J, Abdelaziz M, Lorite J, Perfectti F
Departamento de Ecología.
Ann Bot. 2014 Jan;113(2):237-49. doi: 10.1093/aob/mct186. Epub 2013 Aug 21.
How generalist plants diverge in response to pollinator selection without becoming specialized is still unknown. This study explores this question, focusing on the evolution of the pollination system in the pollination generalist Erysimum mediohispanicum (Brassicaceae).
Pollinator assemblages were surveyed from 2001 to 2010 in 48 geo-referenced populations covering the entire geographic distribution of E. mediohispanicum. Bipartite modularity, a complex network tool, was used to find the pollination niche of each population. Evolution of the pollination niches and the correlated evolution of floral traits and pollination niches were explored using within-species comparative analyses.
Despite being generalists, the E. mediohispanicum populations studied can be classified into five pollination niches. The boundaries between niches were not sharp, the niches differing among them in the relative frequencies of the floral visitor functional groups. The absence of spatial autocorrelation and phylogenetic signal indicates that the niches were distributed in a phylogeographic mosaic. The ancestral E. mediohispanicum populations presumably belonged to the niche defined by a high number of beetle and ant visits. A correlated evolution was found between pollination niches and some floral traits, suggesting the existence of generalist pollination ecotypes.
It is conjectured that the geographic variation in pollination niches has contributed to the observed floral divergence in E. mediohispanicum. The process mediating this floral divergence presumably has been adaptive wandering, but the adaptation to the local pollinator faunas has been not universal. The outcome is a landscape where a few populations locally adapted to their pollination environment (generalist pollination ecotypes) coexist with many populations where this local adaptation has failed and where the plant phenotype is not primarily shaped by pollinators.
广适性植物如何在不变得特化的情况下响应传粉者选择而发生分化，目前仍不清楚。本研究探讨了这个问题，重点关注广适性传粉植物中西班牙中部糖芥（十字花科）传粉系统的进化。
2001年至2010年，在涵盖西班牙中部糖芥整个地理分布的48个地理定位种群中调查了传粉者组合。使用复杂网络工具二分模块性来确定每个种群的传粉生态位。通过种内比较分析，探讨了传粉生态位的进化以及花部性状与传粉生态位的协同进化。
尽管西班牙中部糖芥种群具有广适性，但所研究的种群可分为五个传粉生态位。生态位之间的界限并不清晰，不同生态位在访花者功能群的相对频率上存在差异。不存在空间自相关性和系统发育信号，表明这些生态位以系统发育地理镶嵌的形式分布。推测西班牙中部糖芥的祖先种群可能属于由大量甲虫和蚂蚁访花所定义的生态位。在传粉生态位和一些花部性状之间发现了协同进化，表明存在广适性传粉生态型。
据推测，传粉生态位的地理变异促成了西班牙中部糖芥中观察到的花部分化。介导这种花部分化的过程可能是适应性游荡，但对当地传粉动物群的适应并非普遍存在。结果是这样一种景观：少数局部适应其传粉环境的种群（广适性传粉生态型）与许多未能实现这种局部适应且植物表型并非主要由传粉者塑造的种群共存。
