Moths draped in stealth acoustic cloak evade bat sonar

Moths can hide from the sonar of feeding bats using their acoustically camouflaged wings. Their evolved stealth adaptation is the result of an array of scales  attached to their wing membranes that absorb ultrasound frequencies emitted by hunting bats, and are the first acoustic metamaterials found in nature.

A University of Bristol team discovered that sound waves from bats that hit the fork-shaped scales found on two species of moth cause them to bend and twist, dissipating the energy. ‘Less sound is reflected back to the bat, and the moth thereby disappears or partially disappears from the bat’s sonar screen,’ explains Marc Holderied, an acoustic biologist at the University of Bristol, UK.