Nothing is quite so delicate as the dance of butterflies on the breeze, and, as new research suggests, nothing is quite so humbling to flight engineers.
After spending several years constructing a small and very calm flight tunnel, scientists at the University of Oxford have taken high-speed digital photographs of free-flying butterflies and the intricate, swirling patterns their wing beats make in wisps of smoke.
This is the first time that anyone has captured images that show what the wing beats of free-flying insects do to the air they flutter on. (Other visual studies have used tethered insects, moths, for example, glued to a lightweight rod.) The red admiral butterflies, moving without restraint, show an extraordinary agility and complexity in their flight. Not only do they use many different wing strokes, they use them on successive wing beats.