The tree also knows that it counteracts the enemy

After hearing the sound of the caterpillar chewing the leaf, the plant reacts to that sound by emitting chemicals that repel the predator.

Trees also know "blows".

Sound can affect how plants germinate and the expression of some of their genes. However, the reason why they are sensitive to sound in the air is still an unresolved mystery.

The caterpillar is eating the leaves.(Photo: Diana Meister / iStockphoto)

In the 2014 study, Rex Cocroft, an expert in bioinformatics , used lasers and audiotapes to record the sound of a caterpillar chewing a mustard leaf. Cocroft delivers this recording to other trees of the same type "listen" for two hours, in a quiet space.

Cocroft's colleague, Heidi Appel, then measured the concentration of unpleasant chemicals produced by plants to prevent predators, such as glucosinolates, that make mustard flavored. The results showed that the " listened " sounds of caterpillars eating leaf plants had higher concentrations of unpleasant odors than average.

"This defense system is very popular. It helps plants avoid wasting creating protective chemicals until they are really needed ," ABC Science quoted Appel.

The team also did the same experiment with harmless wind and insect sounds, but the plants involved did not react at all.

"Our study for the first time shows an ecological reason for detecting plant vibrations," Appel said.