The mystery of the twisty flower

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first_imgOn mountains in western Cameroon, the bright red Impatiens frithii flower shares its pollinator, the sunbird, with four other Impatiens species. Unlike these other species, the nectar spur of I. frithii—an elongated sepal containing nectar—curves not downward, but slightly upward, as shown in the above picture. At first, scientists thought this unusual shape would make it hard for sunbirds to sip from the spur. But after recording birds visiting the flower, researchers discovered that when a sunbird forages on the nectar, the flower twists as the spur conforms to the shape of the bird’s bill (as in this video). The small rotation allows the flower’s pollen to land on the underside of a bird’s bill or head, whereas pollens of the other Impatiens species land on the upper side, the team reports today in Current Biology. This way, the flower ensures that its pollen is passed only to flowers of the same species, not to those of closely related species—a move that reduces competition.last_img

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