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 fruit flies to study the basic components of emotion, a new study reports that a fly's response to a shadowy overhead stimulus might be analogous to a negative emotional state such as fear.

Source: Do flies have fear (or something like it)?