Bad news: Plants can hear themselves being eaten

Cocroft and Appel then played back recordings of caterpillar feeding vibrations to one set of plants, but played back only silence to the other set of plants.

When caterpillars later fed on both sets of plants, the researchers found that the plants previously exposed to feeding vibrations produced more mustard oils, a chemical that is unappealing to many caterpillars.

‘What is remarkable is that the plants exposed to different vibrations, including those made by a gentle wind or different insect sounds that share some acoustic features with caterpillar feeding vibrations did not increase their chemical defenses,’ Cocroft said.

‘This indicates that the plants are able to distinguish feeding vibrations from other common sources of environmental vibration.’