Bad news for vegetarians and salad connoisseurs today; apparently plants can ‘hear’ themselves being eaten.
A new study, seemingly taken right from the screenplay of Sausage Party, has found that plants can identify sounds in their environment and react accordingly with defence mechanisms.
Researchers at the University of Missouri discovered that plants, upon hearing the crunch of a caterpillar devouring their leaves, release mustard oils, which are unappealing to caterpillars and ward them off.
Heidi Appel of the Bond Life Sciences Center at MU:
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.
We found that ‘feeding vibrations’ signal changes in the plant cells’ metabolism, creating more defensive chemicals that can repel attacks from caterpillars.
Appel, senior research scientist in the Division of Plant Sciences in the College of Agriculture, Food and Natural Resources collaborated with Rex Cocroft, professor in the Division of Biological Sciences at MU.
Their study saw Arabidopsis, a small flowering plant related to cabbage and mustard, subjected to the chewing of a caterpillar. Cocroft used tiny lasers to measure the plant’s movement response.
The researchers proceeded to play recordings of caterpillar feeding vibrations to one set of plants, and only silence to another set of plants.
When caterpillars later fed on both sets of plants, those previously exposed to feeding vibrations produced more mustard oils, a defensive chemical to ward off caterpillars, than the other test group of plants.
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.
This indicates that the plants are able to distinguish feeding vibrations from other common sources of environmental vibration.
The study, funded in part by the National Science Foundation was published in Oecologia, and the results could be applied to agricultural sectors.
The initial study shows that plants – while they do not have consciousness – may have the potential to illicit their own defence mechanisms from certain pests and crop killers, when certain vibrations are omitted.
Researchers are yet to state whether these vibrations will be effective against vegetarians, at this early stage.