Israeli researchers have uncovered a fascinating aspect of ecological interactions, revealing that female moths use ultrasonic sounds emitted by tomato plants to make decisions about where to lay their eggs. This discovery, reported by Tel Aviv University, underscores the intricate relationships that exist within ecosystems and how different organisms communicate.

The research builds on previous findings which indicated that plants experiencing stress, such as dehydration, produce ultrasonic sounds that go undetected by humans but are within the hearing range of various animals. The team set out to investigate whether insects were capable of perceiving and reacting to these sound signals.

Focusing specifically on moths, which typically lay their eggs on plants to provide sustenance for their larvae post-hatching, the researchers aimed to understand if the presence of distress sounds influenced the moths' egg-laying choices.

In one experiment, female moths were placed in an environment where they could choose between two boxes, isolating auditory signals from other plant characteristics like scent and color. One box had a speaker playing the ultrasonic noises of dehydrated tomato plants, while the other remained silent.

The results showed that moths were drawn to the box emitting sound, suggesting that they interpreted the ultrasonic signals as indicative of a viable living plant, even in a stressed state. However, when researchers blocked the moths' auditory organs, the preference vanished, confirming their reliance on these sounds.

In a subsequent test, the moths faced a choice between two healthy tomato plants, with one plant positioned next to a speaker emitting distress signals from a dehydrated plant. In this scenario, the moths opted for the silent plant, indicating a tendency to avoid stressed plants when healthy alternatives were present.

A further experiment involved offering the moths a choice between a silent box and another containing male moths that also produce ultrasonic sounds. The females showed no discernible preference, laying their eggs equally in both boxes, highlighting their selective response to plant sounds.

The researchers clarified that, in decisions regarding egg-laying, female moths are specifically attuned to sounds emitted by plants, rather than responding to similar sounds produced by male moths.

The findings of this study have been published in the journal eLife, setting the stage for future exploration into the acoustic interactions between plants and animals. The researchers believe that this study merely scratches the surface of understanding the multifaceted ways in which sound influences ecological relationships.

(Cover: A small emperor moth. /VCG)