SECRETS OF BUMBLEBEE FLIGHT

Probably you’ve heard it said that modern science has proved beyond doubt that in fact a bee cannot fly.

Writing in the Nature supplement, Neil Savage traces that absurdity to its origins in 1934 and the work of two French scientists investigating the capability he describes in this way:

The flight of the bumblebee is a remarkable feat. These bees and related species can fly long distances to find flowers, then pause and hover in place, shrugging off powerful guests of wind. They can zip around while laden with more than half their weight in pollen or nectar. And altitude is no issue. ...

Consider: Robert Dudley, an integrative biologist who heads the Animal Flight Laboratory at UC-Berkeley, once studied the flight capabilities of honeybees in the Himalayas, at altitudes of 3,250 meters (10,600 feet) and up.

He placed the bees in a portable pressure chamber and used an air pump to remove some of the air and simulate higher altitudes. The bees lengthened their wing strokes and all were able to hover at pressures equivalent to 7,400 meters above sea level. The champion bee reached 9,125 meters — well above the peak of Mount Everest, at 8,848 meters. …
He does not have a good explanation for this range of ability. “You just have to wonder, why would this come up in nature?”

There’s no good answer for that, but the source of the Frenchmen’s perplexity is simpler: They tried to understand bumblebee design in terms of a fixed-wing aircraft, with its well-known vulnerabilities to eddies and turbulence, which bees create in great quantity.

But bees are not fixed-wing things. They don’t have so much in common with birds, either.

Their wings beat at up to 240 strokes per second, the angles constantly adjusting to airflow over their surface; also, each wing stroke is followed by one in the reverse direction, so the vortex created by one stroke is neutralized by an opposite vortex from the next.

This knowledge is not without useful implications for aeronautical engineering. There is some possibility, Savage writes, that studying bees’ sensing mechanisms could lead to more turbulence-resistant airliners, or in the nearer future, improved design of drones.

How about this: Bee-sized robots that could be flown by remote control into collapsed buildings, following an earthquake, to gather information for rescuers? Or fitted out to serve as artificial pollinators for crops, should we need to replace the natural ones so under threat these days?

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