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 90 birds and Old World flowers DHJanzen101102.jpg high resolution
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And an even closer look at the Erythrina flowers in image DHJanzen101100.jpg above. But note one little detail. The red tubular flowers are pointed downward, instead of out at right angles to the branch, as they would be a neotropical species of Erythrina. Hmmm. Indeed, these Kenya Erythrina flowers are pollinated by birds, but not by hummingbirds. Rather, they are pollinated by sunbirds (Nectariniidae) who perch on the stem below the inflorescence and put their bill upward into the flower. Sunbirds have quite striking convergence on hummingbirds, and are often dressed in the bright and irridescent colors of hummingbirds, are small, fast, and even been subject to the same taxonomic oversplitting of genera in their naming. Think what would happen were hummingbirds to be introduced into Africa. In a very short time they would be creating similar yet different pollen shadows for these bird-pollinated plants, and the unsuspecting biologist would easily conclude that they had coevolved with these flowers. It would be an example of ecological fitting, however, rather than coevolution. |
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