Moths draped in stealth acoustic cloak evade bat sonar

Scales on the wings of moths form acoustic camouflage that hides the insects from the sonar of bats. Researchers examined the Chinese tusar moth (Antheraea pernyi) and Dactyloceras lucina, a large African moth. These species have no ears to hear approaching predators. Instead, they defend themselves using a dense array of tiny, thin scales that each resonate at a particular frequency. Together, the scales absorb at least three octaves of sound — the first known natural acoustic metamaterial. The intricate arrangement and structure of the scales could inspire ultrathin sound-absorbing materials.