When plants are exposed to the vibrations that chewing caterpillars make, they expel a fluid the attackers dislike.
Sorry, vegetarians, but plants know you’re eating them.
At least that is what can be concluded according to a new study by researchers at the University of Missouri in the United States.
Research done on plant responses to acoustic vibrations “found that feeding vibrations signal changes in the plant cells’ metabolism, creating more defensive chemicals that can repel attacks,” said senior plant scientist Heidi Appel.
Using a laser and a tiny piece of reflective material on the leaf of the plant, Rex Cocroft, a professor in the division of biological sciences, was able to measure the movement of the leaf in response to the chewing caterpillar, the university said.
“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.”
Cocroft said: “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 defences.
“The plants can distinguish feeding vibrations from other common sources of environmental vibration.”. .