Researchers at the University of Missouri (MU) found that plants respond defensively to the sounds of themselves being eaten.
The researchers found that plants can identify sounds nearby, such as the sound of eating, perceive this sound as a threat, then react to it.
“Previous research has investigated how plants respond to acoustic energy, including music. However, our work is the first example of how plants respond to an ecologically relevant vibration,” said Heidi Appel, senior research scientist in the Division of Plant Sciences in the College of Agriculture, Food and Natural Resources and the Bond Life Sciences Center at MU.
“We found that ‘feeding vibrations’ signal changes in the plant cells’ metabolism, creating more defensive chemicals that can repel attacks from caterpillars.”
Heidi Appel collaborated with Rex Cocroft, a professor in the Division of Biological Sciences at MU.
In the study, caterpillars were placed on Arabidopsis, a small flowering plant related to cabbages.
Using a laser and a piece of reflective tape, they were able to measure the movement of the plant’s leaves in response to the chewing caterpillar.
“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.”
Appel and Cocroft shared that future research will focus on how vibrations are sensed by plants, what features of the complex vibrational signal are important, and how the mechanical vibration interact with other forms of plant information to generate protective responses to pests.
“Plants have many ways to detect insect attack, but feeding vibrations are likely the fastest way for distant parts of the plant to perceive the attack and begin to increase their defenses,” Cocroft said.
“Caterpillars react to this chemical defense by crawling away, so using vibrations to enhance plant defenses could be useful to agriculture,”Appel said.
“This research also opens the window of plant behavior a little wider, showing that plants have many of the same responses to outside influences that animals do, even though the responses look different.”
This study obviously needs more research, so it’s safe to say that we can still eat salads without worrying that we’re hurting it.