Adaptive significance of floral color change from the viewpoint of cognitive learning and spatial use behavior in pollinators

通过结合动物视觉评价花色的方法、系统发育对性状进化的影响以及性状间的系统发育独立相关性，我们对219种被子植物的花色变化进行了筛选。我们检测到(I)花颜色变化量的显著系统发育信号；(Ii)花颜色变化的进化似乎受到色素化学的限制；(Iii)花颜色变化与蜜蜂授粉之间在进化意义上的可能联系。这些结果与我们的实验室实验结果很好地一致，在实验室实验中，我们发现同样的大黄蜂比不变色的大黄蜂更频繁和持久地访问变色植物。与这些结果一致的是，我们在野外观察中进一步发现，花卉变色的Weigela物种在繁殖过程中对蜜蜂传粉者的依赖程度比其不变色的同类物种更强。

By integrating approaches for evaluating floral colour through animal vision, phylogenetic effects on trait evolution, and phylogenetically independent correlations among traits, we conducted a screening search for floral colour change in 219 angiosperms species. We detected (i) a significant phylogenetic signal in the amount of floral colour change; that (ii) the evolution of floral colour change appeared constrained by pigment chemistry; and (iii) a possible association between floral colour change and bee pollination in an evolutionary sense. These results agree well with those from our laboratory experiments, in which we found that color-changing plants were visited by the same bumble-bee foragers more frequently and persistently than non-color-changing ones. In consistent with these results, we further found in field observations that a floral color-changing Weigela species depends more strongly on bee pollinators in reproduction than its non-colour-changing congener.