Scientists uncover how earless caterpillars detect sound, paving way for novel microphones
Researchers found that tobacco hornworm caterpillars use ultra-sensitive body hairs to hear airborne sounds, a discovery that could inspire new microphone technology.
A team of biologists and engineers studied tobacco hornworm caterpillars inside an anechoic chamber to decipher how the insects sense predators without conventional ears. Using an accelerometer, they first measured reactions to platform vibrations, establishing a threshold below which the caterpillars remained still. When exposed to airborne sound at sub-threshold vibration levels, the caterpillars still responded, implying true acoustic hearing.
Microscopic examination revealed dense sensory hairs on their bodies; removing these hairs markedly reduced defensive movements across frequencies. The findings point to a hearing mechanism based on particle-velocity detection, offering a blueprint for low-cost, direction-sensitive microphones that could improve hearing-aid designs.
