Researchers at Tel Aviv University discovered for the first time that animals respond to sounds made by plants. The study, published in the journal eLife, found that female moths avoid laying eggs on tomato plants that emit distress sounds associated with water shortage.
"This is the first evidence that an animal responds to sounds produced by a plant," said Professor Yossi Yovel of Tel Aviv University, according to BBC News. The findings suggest that there is an invisible ecosystem between animals and plants, where they may communicate in previously hidden ways.
In the experiments, the researchers presented female moths with two healthy tomato plants: one was silent, and the other had a speaker playing sounds emitted by a dehydrated plant. The moths showed a preference for the silent plant, indicating they avoid laying eggs on potentially unhealthy plants.
According to the researchers, the sounds emitted by the plants are ultrasonic, beyond the hearing range of the human ear, but moths can hear them. It was assumed that the moths search for the best place to lay eggs—healthy plants that can properly nourish the larvae.
Further experiments confirmed that the moths' choices were guided specifically by sound and only to sounds from the plants. When the researchers neutralized the moths' hearing organs, their preference for the silent plant disappeared, and they chose between the two plants equally.
"This is a huge, almost completely unknown world," said Professor Lilach Hadany from the research team. The finding is important not only for animals but also for inter-plant communication.
Two years ago, the same group of scientists was the first to prove that plants emit ultrasonic sounds when they are stressed or unhealthy, including clicks similar to popcorn popping. These sounds cannot be perceived by humans but can be detected by animals.
Professor Yovel explained, "After we proved in the previous study that plants produce sounds, we assumed that animals capable of hearing these high-frequency sounds may respond to them and make corresponding decisions." The study confirms that insects both hear sounds made by plants and take them into account in decision-making.
The researchers emphasize that plants do not have consciousness, feelings, or sensory perception. The sounds produced by plants are generated through physical effects caused by changes in their local conditions and are not intentional.
The discovery shows that these sounds can be useful to other animals and possibly to plants that are able to perceive them. "You can think that there could be many complex interactions, and this is the first step," said Professor Yovel, according to BBC News.
The team plans to investigate the sounds that different plants emit and whether other species make decisions based on these sounds. They are also examining whether plants can transmit information to each other through sound and act in response, such as conserving water in drought conditions.
"This is an immense, unexplored field—a whole world waiting to be discovered," Professor Hadany said. The researchers believe that if it is proven that plants and animals have developed the ability to communicate through sound, it would indicate mutual evolutionary benefits.
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