Staring directly into the eyes has a powerful intimidating effect, and many species have evolved staring eye-spots as self-defense mechanisms. Many moths have a pair of startling eye-markings on their wings. These lie concealed until the creatures are attacked by predators. The wings then open and flash the bright eye-spots in the face of the enemy. It has been proved experimentally that this exerts a valuable intimidating influence on the would-be killers, who frequently flee and leave the insects unmolested.
It’s amazing how well defined the eye-spots are.
