Data from: The role of pollinators in floral diversification in a clade of generalist flowers

Pollinator-mediated evolutionary divergence has seldom been explored in generalist clades because it is assumed that pollinators in those clades exert weak and conflicting selection. We investigate whether pollinators shape floral diversification in a pollination generalist plant genus, Erysimum. Species from this genus have flowers that appeal to broad assemblages of pollinators. Nevertheless, we recently reported that it is possible to sort plant species into pollination niches varying in the quantitative composition of pollinators. We test here whether floral characters of Erysimum have evolved as a consequence of shifts among pollination niches. For this, we quantified the evolutionary lability of the floral traits and their phylogenetic association with pollination niches. As with pollination niches, Erysimum floral traits show weak phylogenetic signal. Moreover, floral shape and color are phylogenetically associated with pollination niche. In particular, plants belonging to a pollination niche dominated by long-tongued large bees have lilac corollas with parallel petals. Further analyses suggest, however, that changes in color preceded changes in pollination niche. Pollinators seem to have driven the evolution of corolla shape, whereas the association between pollination niche and corolla color has probably arisen by lilac-flowered Erysimum moving toward certain pollination niches for other adaptive reasons.

传粉者介导的演化分化在泛化支系中鲜有探究，因学界此前假设该类支系中的传粉者施加的选择压微弱且存在冲突。本研究以泛化传粉植物属壁荠属（Erysimum）为研究对象，旨在探究传粉者是否推动了其花部性状的分化。该属物种的花朵可吸引广泛的传粉者类群，但我们先前的研究已证实，可依据传粉者组成的定量差异将该属植物划分为不同的传粉生态位。本文在此检验壁荠属的花部性状是否因传粉生态位的转移而演化：为此，我们量化了花部性状的演化易变性及其与传粉生态位的系统发育关联。与传粉生态位的特征一致，壁荠属的花部性状仅表现出微弱的系统发育信号。此外，花部形态与花色与传粉生态位存在系统发育关联：具体而言，隶属于以长舌大型蜂类为优势传粉者的生态位的植株，其花冠呈淡紫色且花瓣呈平行排列。进一步分析显示，花色的演化早于传粉生态位的转变。研究结果表明，传粉者似乎驱动了花冠形态的演化，而传粉生态位与花冠颜色之间的关联，可能源于淡紫花壁荠属植物因其他适应性原因，向特定传粉生态位类群转移所形成的。