Plants know when they're being eaten

Tuesday, January 6, 2015

University of Missouri scientists Heidi Appel and Rex Cocroft have discovered that plants can tell when they're being eaten and, moreover, produce chemicals to try and defend themselves. They reported their findings in a paper entitled "Plants respond to leaf vibrations caused by insect herbivore chewing," published in Oecologia journal in July. Many websites picked up the story, and some were downright smug about it. Gizmodo.com's headline began with "Nice Try, Vegans."

The study measured the responses of Arabidopsis thaliana, a Eurasian plant commonly used in scientific experiments, to the played-back vibrations of caterpillars chewing. The researchers found that after the plant was "primed" with chewing vibrations, it responded to being fed on by actual caterpillars with increased output of glucosinolate and anthocyanin defenses.

As a control, the study also measured responses to wind and insect song, and found that these vibrations had no effect on the plants.

This could be just the tip of the spear. The paper theorizes that "'eavesdropping' between plants may be possible," as vibrations travelling from plant to plant through connecting roots, stems or even the air can alert neighbouring plants to the presence of a herbivore. (How do you say "look out" in plant-speak?) Similarly, plants may be able to detect the vibrations of underground predators through their roots.

A University of Missouri video posted on MUNews.missouri.edu theorizes that these findings could be used to find new ways to help plants defend themselves against pest pressure. BF