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Hummingbirds & Heliconias

April 28, 2010

Male and female purple-throated Carib hummingbirds have differently shaped bills and feed on different kinds of flowers.

Transcript

BOB HIRSHON (host):
Hummingbirds and heliconias…I’m Bob Hirshon and this is Science Update.
Many male birds have more brightly colored plumage than females of their species. Not so the purple throated Carib hummingbird. John Kress, a botanist at the National Museum of Natural History, says in this species the sexes are nearly identical, except that females have longer, curvier bills.
JOHN KRESS (Smithsonian National Museum of Natural History):
And the difference in bill shapes has to do with the difference in flowers they feed on.
HIRSHON:
Kress and his colleague Ethan Temeles of Amherst College discovered that the each sex co-evolved with a distinct species of heliconia flower.
KRESS:
It’s not just one species of bird to one species of plant, but one sex // to one species of plant.
What’s more, Kress says the most successful males have territories that are abundant in the females’ preferred flower.
KRESS:
This is the first case we know of where the males are actually defending a nectar source as an attractant for mates.
HIRSHON:
I’m Bob Hirshon, for AAAS, the science society.