How do moths stay aloft? With their antennae, of course. When your wingspan is just three inches across, the slightest breeze becomes a gale, and knowing which way is up becomes a matter of life and death. Now, a research team reports that moths stabilize their flight by using their antennae as gyroscopic sensors.
Rotational inertia keeps a spinning top balancing on its tip: If you try to knock it over, the Coriolis force pushes it to the side instead. The size of that force depends on how fast the top is spinning. Engineers measure the corrective force on calibrated gyroscopes to keep aircraft and ballistic missiles on a level course. And flies stabilize their flight by using their club-shaped hind wings to detect these forces. But no one suspected that moths use a similar strategy. Their antennae are primarily known as super-sensitive odor receptors–used to sniff out females and food from miles away–and researchers had hypothesized that they assist in flight only by acting as air flow sensors. That untested idea had “become part of the lore,” says biologist Sanjay Sane of the University of Washington in Seattle.