Do Plants Have Ears?

 by Eva D

Many people share the common belief that although plants are living, they do not communicate or appear to be aware of their environment. Plants actually communicate at the same volume as a human conversation, we just can’t hear it as it’s such a high frequency. An experiment was held where plants were put under stressful conditions such as having their stems cut or receiving no water for a few days. Microphones detected popping noises emitted from the stressed plants which were much quicker than in non-stressed, completely healthy plants.

There is very little research suggesting the evolutionary benefits of these noises or which organisms may respond to them. Interestingly, despite our limited knowledge on the effects of producing sound, scientists have discovered benefits of plants’ abilities to detect sound. While plants do not have ears, they are able to detect sound through cell vibrations and a complicated network of mechanoreceptors.

Three plants of the same species were each played a different audio: the first - silence, the second - the chewing noise of a caterpillar, and the third - the mating song of a leafhopper (which has a very similar frequency to caterpillar feeding vibrations). A caterpillar was then placed on a leaf of each plant and, unsurprisingly, nothing much changed with the first plant. The second plant however produced more mustard oils which are unappealing to caterpillars.

Finally, the third plant did not react at all to the vibrations. Not only does this tell us that plants can detect the vibrations made by predators, but they are capable of distinguishing these from other very similar insects. I would like to point out that plants do not have a nervous system and are not conscious of the defence mechanisms they display, but these discoveries give us insight into the complexity of such organisms. Plant behaviour is an area of ongoing research and hopefully in the near future, the significance of plant communication will be made apparent.