Moths have developed stealth acoustic cloaking to evade bat sonar | Boing Boing

Moths have evolved stealth acoustic cloaking to evade bat sonar | Boing Boing

Researchers intently studied the wings of two moth species from China and Africa, and located that their tiny scales type a “metamaterial” that absorbs bat sonar — thus changing into an acoustic cloaking system.

Fairly darn cool. The paper is paywalled here, however Nature has a good lay-persons’ writeup …

The researchers measured the acoustic reflections from wing sections of two moth species (native to Africa and China) within the ultrasonic vary of 20–160 kHz usually utilized by bats for finding prey. They made measurements each with and with out the tiny scales that usually cowl the wings, that are identified already to offer thermoregulation and optical camouflage. The presence of scales considerably reduces the mirrored sign from the wings by absorption. In distinction, for 2 species of butterfly that aren’t topic to bat predation, the scales truly improve the acoustic reflection. [snip]

Neil et al. discover, nonetheless, that moth scales have variations in dimension and form that each experimental measurements and finite-element modelling reveal to own a variety of resonances, turning the size layer right into a metamaterial acoustic array with a broad absorption band spanning from 20 to 160 kHz. Once more, this contrasts with butterfly scales, which are usually slightly uniform in form and dimension. What’s extra, the modelling research recommend that the positioning of the scales on a versatile membrane base creates coupling and mixing of the acoustic modes to supply an emergent broadband response — an important attribute, maybe, for species preyed on by many alternative types of bat that use completely different frequencies for his or her sonar.

BTW, that picture of a moth above — by Andrew Synder Photography, and CC-2.0-licensed on his Flickr stream — is just a few random moth, I do not assume it is one of many species they studied.

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