How does butterflies fly

Biologists from Sweden's Lund University set out to test a year-old theory, that butterflies "clap" their wings together, pushing out the trapped air to create a jet and push the animal in the opposite direction.

They have a very extreme wing shape -- very large, short but very broad wings compared to their little body," Per Henningsson, associate professor in biology at Lund University, told CNN.

The biologists studied free-flying butterflies, and in their aerodynamic analysis, found the creatures' wings form a cupped shape during the upstroke and "clap," thrusting the butterfly forward. Robert Kacmarcik, Green Valley, Arizona Flat-winged insects also generate lift by using their wings as airfoils, says Robert Dudley, research associate at the Smithsonian Tropical Research Institute and professor at the University of California, Berkeley.

Marysue Vidro, Columbia, Maryland Ozone, no matter where it occurs or how it is created, is both protective and reactive, says Pat Neale, senior scientist at the Smithsonian Environmental Research Center. How do scientists measure water flow in rivers and streams? Howard J. That sort of behavior is going to improve the clap because it forms an air pocket between the wings which, when the wings collapse, that makes the jet even stronger and more efficient. Because the wings are so big, they make it easier for the insect to maneuver.

Butterflies also use their wings to make an erratic fluttering pattern, which is unique to butterflies and very hard for predators, especially birds, to predict which way they will fly. Rather than flapping their wings up and down like birds, butterflies contract their bodies making a slanted figure eight pattern with their wings.

What causes the radical transformation from caterpillar to butterfly? How does a caterpillar rearrange itself into a butterfly? What happens inside a chrysalis or cocoon? Butterfly is believed to be an English word, and there's a few different potential origins. There is the old English word for butterfly which comes from a butter-colored fly. In Great Britain there is a very common butterfly that is yellow. It's called the brimstone. It's kind of a buttery color, so people might think, well maybe it came from the brimstone butterfly.

It had butter-colored wings, or was a butter-colored fly before they knew the difference between flies and butterflies. So that's one hypothesis. So another guess is that the name butterfly came from those butterflies that were trying to feed from the buttermilk and that led to the name butterfly. We're not completely sure but there are two really interesting ideas and fun to think about for sure.

Listen to the full episode to learn about how planes and rockets fly with help from the Smithsonian National Air and Space Museum. For an animation of how things fly, visit the Smithsonian's How Things Fly site. Read the full transcript. VPR News.