Flowering plants are characterized by an astonishing diversity of flowers of different shapes and sizes. This diversity has arisen in adaptation to selection imposed by different pollinators including among others bees, flies, butterflies, hummingbirds, bats or rodents.
Although several studies have documented that pollinators can impose strong selection pressures on flowers, our understanding of how flowers diversify remains fragmentary. For example, does the entire flower adapt to a pollinator, or do only some flower parts evolve to fit a pollinator while other flower parts may remain unchanged?
The researchers could show that flower shapes have evolved in adaptation to the distinct pollinators, but that flower shape evolution was not homogeneous across the flower. In particular, the showy sterile organs of flowers (petals) adapted to the different pollinators more quickly than the rest of the flower: the reproductive organs have evolved more slowly.
"This study is among the first to analyse the entire 3-dimensional flower shape, and it will be exciting to see whether similar evolutionary floral modularity exists in other plant groups", concludes Dellinger.