Impressive camouflage has been developed to avoid identifying butterflies and moths, but no form of visual camouflage can prevent bats – their top predators – from finding them, including their echolocating ability. However, after a million5 million-year-old race of evolutionary weapons, researchers believe they can discover insects that can. Being an insect is a tough fight for uninterrupted survival. Hunters wait for each turn, looking for their next instant food, and avoiding these predators is no easy feat.
The scales of sound-absorbing material (resonant absorbers) have an extremely thin layer that covers the wings, light enough to allow flight but dense enough to absorb sound and make their acoustic footprints almost invisible. Previous studies have shown that moths have a layer of sound-absorbing material in their body, but this layer is too dense for a wing to function. Researchers believe that through clever engineering, evolutions have created resonant absorbers on their wings that are so narrow and light that they do not block the moth’s plane.
In a study published in PNAS, researchers at the University of Bristol have identified an incredible layer of acoustic-damp material that sits on top of a moth’s wing that can absorb bat echolocating waves, according to a study published in PNAS. By absorbing the sound and preventing the echo from fluttering its wings, the insect can avoid solid detection and survive in places where butterflies and other insects cannot. This was the first time that a naturally occurring acoustic metamaterial was discovered.
The wavelength of the shovel is less than what it absorbs and the lexical metal works. If the sound hits an element smaller than the wavelength, it cannot reflect the insect, and in the case of moths, it will be recognizable to bats. More impressively, the researchers believe that moths have an array of different resonators tuned at different frequencies so that a range of wavelengths can be absorbed by the material.
The researchers hope the new discovery could be used effectively to create thinner and more effective sound absorbers for studio and office use. “This promise is one of the thinnest noise absorbers for our homes and offices.