Moths use plant sounds to pick where to lay eggs, avoiding noisy options

Breakthrough discovery shows that moths listen to plants — and avoid the noisy ones

In an extraordinary development in our knowledge of insect behavior, recent scientific studies have shown that moths can recognize sound signals from plants — and they seem to favor those that are less noisy when deciding on egg-laying locations. This finding changes long-standing beliefs about how insects relate with their surroundings and introduces new pathways for research in ecological communication.

The study’s findings suggest that moths, far from being passive navigators of the natural world, are acutely attuned to the subtle sounds emitted by the plants around them. More significantly, their ability to “listen” seems to influence crucial decisions, such as selecting host plants for their larvae. Plants that produce more sound — particularly those under stress or under insect attack — are often avoided.

Although it’s well-known that animals react to sounds, the notion that insects such as moths may react to the sound emissions of plants is quite new. So far, the interaction between insects and plants has been mostly explored through chemical signals: fragrances, pheromones, or visual indicators such as color and form. However, this auditory aspect introduces another layer to the intricate conversation of nature.

The process is both refined and understated. Plants experiencing stress — whether from lack of water, physical injury, or being fed on by herbivores — have the ability to release minuscule vibrations or ultrasonic noises. While these sounds cannot be heard by humans, they can be detected by other living beings. These vibrations might serve as indirect alerts of distress, possibly signaling low nutritional value, an increased number of predators, or a diminished likelihood of survival for any eggs deposited in the area.

Moths, in turn, appear to have developed a sensitivity to these vibratory cues. In experimental settings, they consistently opted for plants that emitted less sound — particularly those that were healthy and not under any evident stress. This suggests that the auditory profile of a plant plays a key role in insect decision-making, particularly for species that invest in finding the optimal site for egg deposition.

This finding has profound implications for ecology, agriculture, and even pest management. If insects like moths are using sound to assess plant health, this raises questions about how widespread this phenomenon is. Could other insects also be using sound to make foraging or reproductive decisions? And might farmers one day use plant acoustics as a way to influence insect behavior, guiding pests away from crops without the use of chemicals?

In practical terms, this research could eventually contribute to more sustainable agricultural practices. By understanding how insects perceive the “soundscape” of a field, it may be possible to engineer environments that are acoustically unattractive to pests. This could be accomplished either by manipulating the sound profile of plants or by introducing non-harmful background noise that masks desirable plant cues.

There is also the intriguing possibility that plants themselves are using sound as a form of passive defense. By emitting ultrasonic cues under stress, they might be signaling to potential egg-layers that they are already compromised — a form of honesty that may benefit both plant and insect in the long run. The plant avoids further damage, and the insect avoids investing in a host that offers low survival prospects for its offspring.

What makes this development especially exciting is that it reshapes our perception of plants as passive organisms. Increasingly, studies are revealing that plants are far more dynamic than previously believed. From sending chemical alerts to neighboring plants to adjusting their behavior based on touch and even light direction, plants are active participants in their ecosystems. The addition of sound-based signaling adds yet another layer to this growing picture of plant intelligence and agency.

The implications for biodiversity are equally compelling. Understanding the nuanced ways in which plants and insects interact — beyond the visible and chemical — gives scientists a fuller view of ecosystem dynamics. It may explain behaviors in the wild that previously seemed random or unmotivated. Why do certain insects avoid perfectly healthy-looking plants? Why do infestations spread unevenly in a field? The answer may lie in the soundscape — in subtle signals that, until now, have gone unnoticed.

Further studies are required to investigate if this behavior is exclusive to particular moth species or part of a wider pattern seen in night-active insects. This observation also prompts questions about the sensitivity of these insects to various sound frequencies and patterns emitted by plants. Might certain frequencies serve as repellents or attractants? If this is the case, could we replicate those frequencies to influence insect behavior in controlled settings?

Furthermore, there are possible issues to take into account. When insects depend on sound to find appropriate host plants, what occurs in environments with growing noise levels? It has been demonstrated that human activities can disrupt animal communication in multiple forms. Could noise pollution caused by humans interfere with the intricate interactions between moths and plants? If that’s the case, what are the wider consequences for ecosystems that rely on these connections to maintain equilibrium?

There’s also a philosophical aspect to consider. The notion that insects are making choices based on what they hear from plants blurs the lines we often draw between different life forms. It challenges the traditional view of the food chain as a simple hierarchy and encourages us to see nature as a network of continuous, complex negotiations — a world in which even the quietest players have something to say.

While this research is still in its early stages, its potential is vast. The idea that plant acoustics can shape insect behavior opens doors to new scientific disciplines, bridging plant biology, entomology, and bioacoustics. It also invites us to listen more carefully to the world around us, not just with instruments and sensors, but with a sense of wonder at the hidden conversations taking place every day.

As science continues to uncover the acoustic lives of plants and their insect neighbors, we are reminded that nature operates on levels far deeper and more intricate than our senses typically allow. With each discovery, we move closer to understanding — and perhaps participating in — the complex symphony of life that surrounds us.

By Roger W. Watson

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