Thoracic scales of moths as a stealth coating against bat biosonar.
Level 5 - mechanism / opinion, no new human data
Bench and animal acoustic biophysics study (Level 5 by design analogy)
PubMed 32093539 · doi:10.1098/rsif.2019.0692
What was done
Researchers investigated whether thoracic scales in moths act as acoustic absorbers against ultrasonic bat biosonar. Using tomographic echo imaging, they measured echo reflections from the thoraces of diurnal butterflies and earless moths across ultrasonic frequencies (20–160 kHz) and compared empirical findings to numerical models of porous sound absorbers.
What was found
Thoracic scales of diurnal butterflies had negligible impact on ultrasound echo strength, whereas thoracic scales of earless moths absorbed an average of 67 ± 9% of impinging ultrasonic sound energy. This acoustic camouflage operated over a broad frequency range (20–160 kHz). Modeling demonstrated that the scales function as porous sound absorbers with higher absorption efficiency than technical fibrous materials with equivalent structural parameters.
Why it matters
This work identifies a natural, lightweight acoustic metamaterial strategy, showing how earless moths passively reduce biosonar detectability through structural sound absorption.
Limits
The abstract does not provide sample sizes, the specific moth and butterfly species evaluated, or measurements of in-flight predation success in natural ecological encounters.
Cited by
- contradicts Moths possess acoustic meta-reflector structures on their bodies that deflect and dampen incident echolocation energy from bats.