We have had quite a bit of exchange about whether bees can fly. I
happen to know they can, particularly when one lands tail first on my
arm! This morning's Los Angeles Times had a brief account about that
concern, as follows:
SCIENCE FILE
Scientists Vindicated: Bees Can Fly; Here's How
By Thomas H. Maugh II
Times Staff Writer
December 3, 2005
Scientists have long been derided because of mathematical calculations
made in 1934 by French entomologist August Magnan proving that, despite
visible evidence to the contrary, the flight of bees was "impossible."
But now bioengineer Michael H. Dickinson of Caltech and his colleagues
have shown conclusively how the hefty insects manage their aeronautical
excursions.
Dickinson's team used a combination of high-speed digital photography
and a giant robotic mock-up of a bee wing to demonstrate the unusual
mechanics behind bee flight.
The secret, they reported this week in the Proceedings of the National
Academy of Sciences, is a combination of short wing strokes, rapid
rotation of the wing as it changes direction, and very fast flapping.
Virtually all insects flap their wings through a wide arc, about 165
degrees. Frequency generally varies with size: The larger the insect,
the slower the wings beat. Mosquitoes, for example, beat their wings
about 400 times per second, fruit flies about 200. Birds beat their
wings much more slowly — about 50 times per second for hummingbirds.
But bees, which are 80 times as large as fruit flies, flap their wings
230 times per second through an arc of about 90 degrees. And although
most insects produce the majority of lift about halfway through the
stroke, when the wing is moving fastest, bees get an equally large
contribution at the beginning and end of the stroke from the rotation
of the wing.
Bees, moreover, do not vary their beating rate when carrying a load.
Instead, when burdened with pollen, they increase the arc of flapping,
Dickinson found.
"The wings have to operate fast and at a constant frequency or the
muscle doesn't generate enough power," he said.
It is possible that the muscles evolved in this fashion specifically
to support bee flight, he said, but it is equally likely that "bee
ancestors inherited this kind of muscle, and now present-day bees must
live with it."
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I wonder how much that research cost us taxpayers?
Adrian
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