Novel relationships between the floral morphology of introduced plants and the trophic morphology of native pollinators have been hypothesized to cause strong natural selection on both parties, but evidence for such selection is rare. We capitalized on a natural disturbance to examine selection on an introduced plant, Heliconia Wagnerian, on the island of Dominica, before and after Hurricane Maria. Prior to the hurricane, female Anthracothorax jugularis hummingbirds, which have longer bills than males, were the main visitor to H. Wagnerian, and directional selection on corolla length was insignificant. After the hurricane, shorter-billed male A. jugularis were the main visitor to H. Wagnerian. The absence of trait matching between a short-billed pollinator and a long-flowered plant resulted in directional selection for shorter flow-ers because males preferentially visited plants with shorter flowers. The amount of nectar removed by male A. jugularis was negatively associated with flower length, with flowers >53 mm containing nearly five times the nectar than flowers <53 mm. We estimate a roughly 75% decrease in the population size of A. jugularis, and results suggest the heaviest mortality occurred among short-billed male hummingbirds and larger-bodied individuals of both sexes, which would have higher nectar requirements and the most difficulty obtaining nectar. Our results indicate that hurricanes may alter relationships between plants and pollinators and that lack of trait matching resulting from such disturbances may lead to selection on both plant and pollinator.
A hurricane alters pollinator relationships and natural selection on an introduced island plant
Year: 2019
