Hummingbirds take over bees' work.Their wings a blur, hummingbirds This is a complete list of hummingbirds in alphabetical order, sortable by common or binomial name. For hummingbirds in taxonomic order, see list of hummingbirds in taxonomic order Name binomial Allen's Hummingbird Selasphorus sasin Amazilia Hummingbird flit among Western and Southwestern U.S. meadows, oblivious to their effect on other pollinators. Yet over the millennia, they have moved in on bees and butterflies, says Verne Grant, a botanist at the University of Texas at Austin “University of Texas” redirects here. For other system schools, see University of Texas System. The University of Texas at Austin (often referred to as The University of Texas, UT Austin, UT, or Texas . Most of the 129 types of U.S. flowers that now depend on the hummingbirds' visits belong to the Arcto-Tertiary plant group, which did not expand south into hummingbird habitat until 58 million years ago. Indian paintbrushes, part of the genus Castilleja, were early arrivals, he notes. Now, 48 of that genus' 200 species have made the switch from other pollinators to birds, says Grant. These 48 have spread across 24 of 29 plant communities in this region. "Castilleja got in on the ground floor and was a big success," he adds. Other species followed. He knows of 15 members of the genus Penstemon Penstemon a North American genus of plants in the family Scrophulariaceae which act as facultative selenium converters; the selenocompounds produced by the plant cause alopecia, lameness, laminitis; called also beard tongue. that rely on hummingbirds and may have evolved this reliance independently of one another. Seven kinds of columbines also have abandoned bees for birds, but most of the other 16 genera genera, in taxonomy: see classification. with hummingbird pollinators are very recent converts, with just one or two species in each making use of these birds, he adds. Grant thinks the Arcto-Tertiary plants grew alongside flowers already being pollinated by hummingbirds. Because these birds tend to seek out new food sources, they probably visited any newcomer -- especially if their normal food sources were in short supply -- and perhaps proved a reliable pollination pollination, transfer of pollen from the male reproductive organ (stamen or staminate cone) to the female reproductive organ (pistil or pistillate cone) of the same or of another flower or cone. partner for that plant. As a result, the plant evolved flowers more conducive to birds than to bees or butterflies, he suggests in the Oct. 25 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences. . |
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