How These Caterpillars Use Their Body Hair to Listen for Danger

Explore

FNorth American shipowners are all too familiar with tobacco hornworms. These smooth lime green caterpillars, which appear to be made from Play-Doh, are notorious agricultural pests. Tobacco hornworms, sphinx moth larvae (Manduca sexta), feed on plants in the Solanaceae family which, you guessed it, includes tobacco but also tomatoes, peppers and eggplants. New research unveiled at an animal bioacoustics meeting identifies a superpower of tobacco hornworms that influences their crop-threatening behavior.

A biologist at Binghamton University had noticed that tobacco worms housed in the laboratory jumped when she spoke. “Every time I booed them, they jumped,” Carol Miles said in a statement. “And so I kind of put it away in the back of my mind for many years.”

Until now.

Read more: “Caterpillars that can kill you”

Miles, along with Binghamton colleagues experienced in researching how animals respond to sound, set up acoustic experiments. Hornworm caterpillars were exposed to low-frequency (150 Hz) and high-frequency (2,000 Hz) sounds while inside a specialized “anechoic” chamber that suppresses all echoes. In anechoic chambers, the quietest rooms in the world, some humans panic when they hear their blood flowing and their joints moving.

But it was the perfect place to determine whether hornworm caterpillars were jumping in response to airborne noises or sound-induced vibrations of their feet. “They’re still on the stem of the plant, so we thought maybe the vibration of the plant was why they were detecting the sound,” explained study author and mechanical engineer Ronald Miles.

By controlling the inputs for sound without vibration, compared to vibration without sound, the researchers found that the caterpillars were 10 to 100 times more sensitive to sounds than to vibrations. Since the caterpillars are thought to lack ears, discovering that they detected sounds inspired more experimentation. Bared caterpillars, which had their fine hairs removed, showed a muted sound response, indicating a sensory role for the hairs.

The research team hypothesizes that this tobacco hornworm caterpillar superpower evolved as an adaptation to escape predatory wasps, which tend to flap their wings between 100 and 200 Hz. If a caterpillar hears a wasp approaching, a quick jump or twitch can put the sweet, tasty larvae out of danger.

Or, the jumping could simply be the sign of a frightened caterpillar moments before it expected to be swallowed up.

Enjoy Nautilus? Subscribe for free to our newsletter.

Main image: Daniel Schwen / Wikimedia Commons

• Devin Reese

  Published on February 2, 2026

  Devin Reese is the editor-in-chief of Natural history and a science writer based in Alexandria, Virginia.