Geographic Flower Trait Variation of Aquilegia buergeriana Sieb. et Zucc. var. buergeriana on Mt. Norikura and the Utsukushigahara Highland, Japan

Many studies have argued the importance of the flower-pollinator size matching for flower trait diversification. However, non-pollinator agents may also influence flower traits. In this study, we investigated the altitudinal variation of flower size (spur length, stamen length, petal blade length, corolla diameter, and sepal length) and flower visitors of Aquilegia buergeriana var. buergeriana (long-spurred columbine) in central Japan. Although this species was primarily visited by Bombus consobrinus, which has an unvarying mouthpart length, flower sizes varied greatly among populations with no correlation with altitude. These results suggest that non-pollinator and non-meteorological agents, directly and/or indirectly, impose selection pressure on flower size in A. buergeriana.