Insects are pretty good at navigating, and seem to know how high they are flying. But how? Dr. Nicolas Franceschini, a roboticist at the French National Research Agency, believes that insects regulate altitude by watching the speed at which the ground below is moving, adjusting their height until groundspeed is optimum.
To test this idea, Franceschini created a robotic insect with an electronic eye for navigation. Tethered to a tiny arm, which it can lift and drag in response to commands like "nose-down" or "nose-up," it has behaved in the lab just like butterflies, which are known, for example, to fly down across the bottom of narrow canyons, rather than over them. Franceschini says the robot's abilities might prove useful in unpiloted spacecraft, airplanes or submarines.