Floral color change was studied inLupinus pilosusL. to elucidate its ecological significance for both the plant and the pollinators. It was found that the change in the banner spot from white to purple was enhanced by artificial pollination. White phase flowers offered more pollen as reward to foraging pollinators than did purple phase flowers. The changes in color and reward were recognized by the pollinators and affected their foraging behavior. Pollinators preferred pre-change flowers and avoided post-change ones, thus increasing the chance that white phase flowers would be pollinated. It is suggested that the increase in outcrossing rate caused by pollinator activity could be the advantage and the driving force for the evolution of the color change mechanism inL. pilosus.
展开▼
