A fruit fly starts buzzing around food at a picnic, so you wave your hand over the insect and shoo it away. But when the insect flees the scene, is it doing so because it is actually afraid? Using ...

video: A single fly walks back and forth, and briefly grooms, before a shadow moves overhead. The fly jumps and freezes in place, its wings and other appendages held motionless.

When fruit flies respond to the threat of an overhead shadow, are they afraid? That's a hard question to answer, say researchers reporting in the Cell Press journal Current Biology on May 14 ...