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A Tale of Two Pollinators
left: Long-tailed Hermit (Phaethornis
Credit & Copyright: Dr. Bruce G. Marcot
Seeing double? In a sense, you are. These two birds are both key
tropical or subtropical plants that bear long, tubular red flowers. But
they live in worlds apart.
On the left is the Long-tailed Hermit, a hummingbird of the Neotropics, here photographed in the lowland rainforest of Costa Rica. It is about to take nectar from -- and inadvertently pollinate -- blossoms of a lobelia plant. Hummingbirds belong to the family Trochilidae of the order Trochiliformes.
On the right is the White-bellied Sunbird, here photogaphed in Zimbabwe, southern Africa, taking nectar from -- and inadvertently pollinating -- blossoms of an Erythrina tree. Sunbirds belong to the family Nectariniidae of the order Passeriformes.
How can these two species be so similar, and perform the same ecological service -- pollination -- in so widely disparate geographic locations and taxonomic groups? The answer is that they constitute what can be termed "functional vicariates," that is, different species that perform very similar ecological roles.
Many other animals perform such pollination roles. Bats pollinate blooms of saguaro cactus. Honeyeaters (birds) of Australia and elsewhere pollinate many flowering plants ... including rare species of eucalpytus. Brush-furred mice (Lophuromys spp.) of South Africa pollinate protea flowers. Giant geckos (Hoplodactylus duvaucelii) of New Zealand pollinate pahutapata tree blooms. And most plant foods of interest to humans are pollinated by bees and other insects. Many other examples exist. Clearly, pollination is a major ecological role which has invited a wide array of actors into its cast.
Next week's picture: Tassel Ears of the Forest
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