An Israeli research team has discovered that female moths decide where to lay their eggs based on ultrasonic sounds emitted by tomato plants.
The discovery provides evidence that plants and animals can interact through sound waves, according to a statement from Tel Aviv University.
In previous research, the team found that plants experiencing stress, such as dehydration, emit ultrasonic sounds that are inaudible to humans but detectable by many animals. In this new study, the team explored whether insects are capable of detecting and responding to these sounds.
They focused on moths, which lay their eggs on plants to provide food for their larvae after they hatch. The team wanted to find out if moths avoid laying eggs on plants that emit disturbing sounds.
In one experiment, female moths were placed between two boxes and isolated auditory factors from other plant characteristics such as color and scent. One box was equipped with a speaker that played a recording of the ultrasonic sounds of a dehydrated tomato plant, while the other box played no sound.
The moths apparently chose the boxes that emitted the sound, indicating that they interpreted the ultrasonic sound as the presence of a living plant, even if the plant was stressed.
When their hearing organs were blocked, they no longer showed a preference for either. The research team said this confirmed that they were responding solely to ultrasonic sounds.
In another test, moths had to choose between two healthy tomato plants, with one plant near a speaker playing an ultrasonic recording of a stressed plant and the other plant making no sound.
This time, the moths chose the silent plant, suggesting that they avoid stressed plants when there is a clear choice.
In a final test, moths were given a choice between a silent box and one containing a male moth, which also produced a similar ultrasonic sound. Female moths showed no preference, laying eggs in both boxes.
The research team explains that, when deciding where to lay eggs, female moths respond specifically to sounds emitted by plants, not similar sounds produced by males.
The findings were published in the journal eLife. The research team said that acoustic interactions between plants and animals exist in many forms and play a wide range of roles. Their research is just the first step in uncovering how plants and animals interact through sound in nature.
