Kat Arney, The Naked Scientists
Kat Arney was all of a buzz this week for her mythconception about the flight of the bumblebee…
Kat - We’re finally moving towards sunnier days and the flowers are blooming. And where you get flowers, you get bees – but looking at a big, buzzing bumblebee making its way from bloom to bloom on tiny wings, you might wonder how on earth it stays airborne. You wouldn’t be the only one – it’s long been held that bumblebees shouldn’t be able to fly, and it’s been repeated by everyone from management consultants and marketeers to US presidential candidates. In 2008, wannabe president Mike Huckabee said "It's scientifically impossible for the bumblebee to fly; but the bumblebee, being unaware of these scientific facts, flies anyway.”
So given that bees obviously can fly, travelling at a rate of 3 meters per second, are they wilfully defying all the proven laws of aerodynamics and science as we know them, or is there something else going on?
One mistake people make when thinking about the flight of the bumblebee is to assume that there are similarities with other winged things, such as birds or aeroplanes. In fact, this is probably where the myth arose, based on calculations of the aerodynamic properties of typical wings from decades ago suggesting that the bumblebee’s wings are too small to lift its weight into the air. But bees are not birds, and they’re built very differently. And simplistic models that assume their wings are rigid like an aeroplane and work in the same way are bound to be wrong.
Rather than being built for life on the wing, soaring freely through the air, bumblebees are the tanker trucks of the insect world, evolved to carry huge loads of pollen back to their hive. To figure out exactly how their wings move to propel them through the air, back in 2009 Oxford University scientists put bumblebees in a wind tunnel with some smoke and high-speed cameras. And although the bees clearly do fly, they do it in an unusual way– unlike most flying animals their left and right wings flap independently and the airflow around them never joins up to help them slip through the air more easily. It’s described best as a ‘brute force’ approach to flying, rather than the elegant soaring of a bird or the streamlined flight of a fly.
What’s more, a bee’s wings are much more flexible than the more rigid feathered wings of a bird. By wiggling and rotating their wings around hundreds of times per second, the bees create what are known as vortices – or to put it simply, mini-hurricanes – that give them the lift they need to say aloft. This is much more similar to the whirring blades of a helicopter rather than the fixed wings of a plane, and nobody goes around saying that helicopters shouldn’t be able to fly.
So – although they may do it in an unorthodox manner, the flight of the bumblebee doesn’t defy physics. In fact, this myth is often used as a way of being disparaging about science – implying that if something doesn’t fit into our current models or we don’t know how it happens then science is somehow at fault or that there a mystical forces at work. Of course, as this story shows, when something appears to defy the laws of physics, it’s because we haven’t found the right way of studying it. So next time you hear someone repeat this myth, tell them to buzz off!