Caterpillars use tiny hairs to hear
Have you ever walked into a room full of caterpillars? While the answer for most people is probably no, those of us who have done it may have noticed that insects respond to the sound of your voice. This is what happened to Carol Miles, a biologist at Binghamton University in New York.
âEvery time I booed them, they jumped,â she said in a statement. “And so I kind of put it away in the back of my mind for many years. Finally, I said, ‘Let’s see if they can hear, what they can hear and why.'”
Miles and the team brought tobacco hornworm caterpillars (Manduca sexta) in one of the quietest rooms in the world: the university’s anechoic chamber. Inside this quiet room, the team was able to precisely control the sound environment, while working to identify bug-triggering sounds.
đThe hearing of this little animal could inspire new generation microphones!
The team understood that the caterpillars had reactions, but didn’t know whether it was to airborne sounds or to the sonic vibrations of the base that they could feel with their feet. Since the caterpillars often hang out on plant stems, the team hypothesized that they may be picking up sounds because of the plant’s vibrations.
In the anechoic chamber, researchers can emit sounds and vibrations independently of each other and understand the type of response they elicit. They studied the caterpillars’ response to airborne sounds and surface vibrations to high (2,000 hertz) and low frequency (150 hertz) sounds.
The researchers found that caterpillars perceive both, although their response to airborne noise is 10 to 100 times greater than that of the surface vibrations they feel through their legs.
The next step was to determine how They heard the sounds and to do this, the team removed certain hairs from them. Although this may seem like a strange strategy, many insects perceive sound through their hairs which detect how they move air. In fact, the team’s caterpillars were less sensitive to sounds after losing hair on their abdomen and thorax. Miles and his colleagues’ theory is that the tobacco hornworm’s hearing might be adjusted during evolution to detect the wingbeats of predatory wasps.
In the world of human hearing, their research could play a role in microphone technology.
The results were presented at a joint meeting of the Acoustical Society of America and the Acoustical Society of Japan in December 2025.
“Sound detection technologies require a tremendous amount of effort and expense, and there are all kinds of microphones made in this world. We need to learn better ways to create them,” added Ronald Miles, study co-author and mechanical engineer at Binghamton University. âAnd the way itâs always been done is by observing what animals do and learning how they detect sounds.â
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