Macroevolution of flower color patterning: biased transition rates and correlated evolution with flower size

Floral pigmentation patterns can both mediate plant-pollinator interactions and modify the abiotic environment of reproductive structures. To date there have been no inquiries into the rate and directionality of macroevolutionary transitions between patterned and non-patterned petals despite their ecological importance and ubiquity across angiosperms. Petals in the Potentilleae tribe (Rosaceae) display color patterns in the ultraviolet (UV) and human-visible spectrum, or can be uniform in color (i.e., patternless). Using a phylogeny of Potentilleae, I test whether evolutionary transition rates between patterned and non-patterned petals are biased in either direction. I then examine whether UV and human-visible patterns are phylogenetically correlated and test the prediction that color patterns will evolve in concert with larger flowers if they function as guides to orient pollinators to floral rewards. I found that transition rates were biased toward petals that were uniform in color. T...

花卉色素斑型既可介导植物与传粉者的互作，也可改变生殖结构所处的非生物环境。迄今为止，尽管色素花瓣与非色素花瓣在被子植物中分布广泛且具有重要生态意义，但学界尚未对二者之间的宏演化转变速率与方向开展相关研究。蔷薇科（Rosaceae）委陵菜族（Potentilleae）的花瓣，既可呈现紫外（ultraviolet，UV）波段与人类可见光波段的色彩斑型，也可表现为通体单色（即无斑）。本研究依托委陵菜族的系统发育树，检验色素花瓣与非色素花瓣间的演化转变速率是否存在方向性偏向；随后检验紫外斑型与可见光斑型是否存在系统发育相关性，并验证如下假说：若色彩斑型的功能是作为传粉导向信号，指引传粉者抵达花报酬，那么色彩斑型将与更大的花型协同演化。本研究发现，演化转变速率偏向于通体单色的花瓣。……