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THE QUESTION LIBRARY HOW WE KNOW
Can Plants Sense a Caterpillar Chewing?
A caterpillar’s bite makes a leaf vibrate. In a lab experiment, those tiny movements changed how the plant responded to later feeding.
THE SHORT ANSWER
Yes, in a laboratory experiment, thale cress responded to vibrations caused by caterpillars chewing its leaves. Researchers replayed recorded vibrations directly through a leaf. Later, when caterpillars fed, plants exposed to the chewing vibrations showed a stronger response in some defense chemicals. The experiment measured how a plant responded to movement in its tissues.
- A device replayed real chewing vibrations directly through a leaf.
- Exposure changed some chemical responses to later feeding.
- The wind and leafhopper vibrations tested did not prime the same anthocyanin response.
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About this picture
Original AI-generated illustration for God Plays Dice. The golden curves suggest vibrations traveling through the leaf.
WHERE THE EVIDENCE STANDS
How sure are we?
- Leaf-borne chewing vibrations can change later defense chemistry in thale cress.The experiment compared several vibration treatments and measured chemical responses.
- Does the vibration response reduce feeding damage outdoors?The cited experiment measured plant chemistry in the laboratory.
- The chewing experiment establishes that the plant consciously hears.The researchers measured movement and chemical responses rather than subjective experience.
WHAT WE DON’T KNOW YET
How plants detect the chewing pattern and how much the response protects them outdoors remain open questions.
WHAT WOULD CHANGE THIS ANSWER
Outdoor experiments that isolate chewing vibrations and measure leaf damage or caterpillar growth would show whether the response protects the plant in the wild.
A caterpillar takes a bite, and the leaf moves a little. That movement can travel through the plant. Researchers wanted to know whether those vibrations could change how the plant responds when it’s eaten.
THE LONG ANSWER
Free long answer 1 of 3 this month.
How did researchers replay a caterpillar’s bite?
In the original experiment, Heidi Appel and Reginald Cocroft used a laser to measure the tiny movements of thale cress leaves while cabbage white caterpillars fed. They used a small device attached to a leaf to reproduce those vibrations on another plant. That let them test the movement by itself before allowing caterpillars to feed. Think of tapping one end of a table and feeling the tap at the other end. The solid surface carries the movement.
What did the plant do differently?
After caterpillars fed, plants that had experienced the chewing vibrations showed higher levels of some compounds called glucosinolates. In a separate experiment, the chewing vibrations alone did not raise the levels of the compounds measured in that part of the study. After feeding, however, plants exposed to chewing vibrations produced more of a group of pigments called anthocyanins. The wind and leafhopper mating vibrations tested did not produce that same response.
Biologists call this kind of change priming. An earlier cue changes the response to something that happens later. The results tell us about particular chemicals under those test conditions. How much this would protect a plant outdoors, where many vibrations arrive together, is still an open question.
Does this mean plants can hear?
“Hearing” usually brings ears and airborne sound to mind. In this test the vibrations traveled through the leaf. The researchers measured changes in plant chemistry. Whether anything feels like sound to a plant is a separate question. Our Library answer on animal feelings and plant signals explains why that distinction matters.
In a follow-up study, researchers found that chewing by different caterpillars produces repeated pulses, although the rate varies. In a separate study of tomato and tobacco plants, microphones picked up ultrasonic clicks emitted by stressed plants. That second experiment addressed what plants emit into the air. The chewing experiments asked how plants respond to movement in their own tissues.
Keep asking
Do animals have feelings like we do?
There is strong scientific support for conscious experience in other mammals and birds, and a realistic possibility in many other animals, including octopuses.
New here?
God Plays Dice answers big questions in plain words, with sources and one of six honest labels.
Words worth knowing (3)
- Thale cress
- A small flowering plant also called Arabidopsis thaliana, widely used in plant experiments.
- Glucosinolate
- A chemical compound found in plants of the mustard family that can play a role in defense.
- Priming
- An earlier cue changes how an organism responds to a later event.
Sources & further reading
(3) · Checked Nov 9, 2026
- Plants respond to leaf vibrations caused by insect herbivore chewing ↗Oecologia · Springer NatureOriginal experiment measuring plant chemistry after playback of leaf vibrations and subsequent feeding.
- Leaf vibrations produced by chewing provide a consistent acoustic target for plant recognition of herbivores ↗OecologiaFollow-up measurements of chewing vibration patterns and tests with thale cress.
- Sounds emitted by plants under stress are airborne and informative ↗Cell · Tel Aviv University research portalA separate experiment measuring ultrasonic sound emitted into the air.
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