Plants, a key part of the caterpillar’s diet, can sense changes in their environment, such as light, temperature, and touch (Weissmann, 2014). However, in 2014, a study at the University of Missouri conducted by Heidi Appel and Richard Cocroft found that plants can also “hear” the vibrations from a caterpillar’s chewing movements. 

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The experiment began in 2008, when 22 different caterpillars’ feeding patterns were studied using the Arabidopsis mustard plants as food. A laser beam was pointed on a piece of reflective tape adhered to the plant, and when caterpillars chewed, the laser would measure each small movement or vibration (Karstens, 2014). After the laser captured the microscopic movement, it shifted the vibration to a human hearing range, allowing scientists to listen to the vibrations (Karstens, 2014). Appel and Cocroft then used a device to mimic the caterpillars’ feeding movements using the vibration patterns they had collected, and tested how the plants responded (Karstens, 2014). They found that the plants that received the sound produced more glucosinolate, which is what gives mustard plants their signature spicy taste (Karstens, 2014). When glucosinolate levels spiked, caterpillars would move away from the plant and stop eating, due to the taste of the leaves (Karstens, 2014). The conclusions of the experiment focused on how the mustard plants would display a defense mechanism in response to the specific vibrations of the caterpillar’s chewing. 

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Additionally, it was found that insects have been using the plants to send certain signals. By chewing, insects send vibrations through the plant, which can protect them from incoming predators (Karstens, 2014). After it detects the vibrations, the plant releases its chemical defenses (Karstens, 2014). This means that the plants actively respond to insect vibrations, suggesting that

they contain a vibration signaling pathway for when their leaves are being eaten (Appel & Cocroft, 2014). The chewing vibrations allow the mustard plants to prepare for subsequent attacks, warding away predators (Weissmann, 2014). The plants could even tell the difference between chewing vibrations, weather, and insect song vibrations (Appel & Cocroft, 2014). This proves that plants do not only listen to the frequencies of the sounds, but they also have a complex system to perceive these sounds (Weissmann, 2014). 

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After this experiment, Appel and Cocroft hypothesised that although only the mustard plant was tested, other plants could also have the ability to hear chewing, or even other noises. (Appel & Cocroft, 2014). Further research will be conducted on other plants and herbivores to see if they also have vibration sensing abilities (Weissmann, 2014). They also intend to introduce other variables that plants might respond to, like light and chemicals (Weissmann, 2014). 

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Comprehensively, the discovery of this physical reaction from plants may change many aspects of agriculture, namely, the use of pesticides in farming. If farmers are able to take advantage of the natural ability of select plants to defend themselves from predators, there would be less demand for artificial pesticides. Not only will this change the market, but it will also change the health and safety of food. Consumers can be more confident that they are not ingesting toxic chemicals. Although there is still a lot of research to be done on this topic, plants’ defense mechanisms can help scientists make more discoveries about their capabilities.

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References 

Appel, H. M., & Cocroft, R. B. (2014, July 2). Plants respond to leaf vibrations caused by insect herbivore chewing. National Library of Medicine. Retrieved January 10, 2026, from https://pmc.ncbi.nlm.nih.gov/articles/PMC4102826/ 

Karstens, S. (2014, December 4). Bad Vibrations: Plants respond to insect chewing. SeedWorld. Retrieved January 10, 2026, from 

https://www.seedworld.com/us/research/2014/12/04/bad-vibrations-plants-respond-insect -chewing/ 

Weissmann, E. (2014, July 10). Plants Listen for Hungry Caterpillars, First-of-Its-Kind Study Suggests. National Geographic. Retrieved January 10, 2026, from 

https://www.nationalgeographic.com/science/article/140709-plants-vibrations-insects-bot any-science