Research has shown that animals and plants communicate with sounds.

A growing body of evidence suggests that plants under stress emit tiny bursts of ultrasound—and some animals are listening. Far from being silent, leaves and stems can click and crackle in frequencies far above human hearing, broadcasting information about drought or damage into the surrounding environment.

Why sound matters in ecology

Ecologists have long focused on chemical scents, colors, and touch to explain how organisms interact. Sound adds a new dimension to that picture. Acoustic signals travel quickly, pass through darkness and foliage, and can be detected from a distance without direct contact. If plants and animals share an acoustic channel, then forests, fields, and gardens may be woven together by a hidden chorus of informational cues.

What the experiments found

Using sensitive microphones, researchers captured ultrasonic clicks emitted by plants experiencing drought or physical injury. These emissions typically fell within tens of kilohertz—well above the threshold of human hearing—and occurred more frequently when the plants were stressed. In other words, stressed plants “spoke” more often.

To probe whether other organisms respond to these signals, flying insects were placed in controlled arenas with speakers playing recordings of stressed plants. Female moths avoided laying their eggs near the sounds associated with ailing vegetation, choosing instead the silence linked to healthy plants. When the insects’ ability to hear was experimentally reduced, that avoidance pattern disappeared, pointing to sound as the decisive cue.

Importantly, the behavior wasn’t limited to speakers. In the presence of actual plants, insects steered clear of those producing the ultrasonic clicks linked to drought or damage. The results suggest that these faint acoustic cues can act as an early warning system, steering egg-laying away from poor-quality food sources for future larvae.

A quiet conversation you can’t hear

Humans cannot perceive these high-pitched clicks unaided, but many animals can. That raises a tantalizing possibility: sound may mediate a wider network of interactions than previously recognized. If moths listen to plants, other species with similar hearing ranges might do the same—predators seeking vulnerable prey, pollinators optimizing for nectar-rich blooms, or even neighboring plants adjusting their own physiology in response to stress signals carried by air.

Implications for conservation and technology

• Early drought detection: Continuous acoustic monitoring could provide rapid insights into water stress in crops and natural habitats, enabling farmers and land managers to intervene before visible wilting occurs.
• Precision agriculture: Integrating ultrasonic sensors into irrigation systems could automate watering decisions, conserving water while maintaining yields.
• Biodiversity monitoring: Soundscapes that include plant emissions, not just animal calls, might offer a richer picture of ecosystem health and disturbance.
• Robotics and remote sensing: Drones or stationary devices equipped with specialized microphones could map plant stress across large areas without physical sampling.

How this reshapes ecological theory

Adding acoustics to the classic trio of chemical, visual, and tactile cues reframes how we think about food webs and habitat selection. The finding that sound can alter reproductive behavior—where and when insects lay eggs—shows that acoustic information doesn’t just accompany ecological processes; it can drive them. Over time, such choices may influence population dynamics, plant–insect coevolution, and even patterns of crop damage.

Open questions

While the evidence is compelling, much remains to be learned. Do different plant species produce distinct acoustic signatures? How far do these signals travel outdoors amid wind and other noise? Which animals are tuned to which frequencies, and how do competing sounds shape behavior? Answering these questions will require field studies across varied habitats, standardized methods for recording and analysis, and careful controls to rule out confounding cues.

A new acoustic frontier

The discovery that stressed plants generate ultrasonic clicks—and that animals can act on those signals—opens a new chapter in bioacoustics. It suggests that life on Earth may be coordinating more through sound than we ever realized. From farms seeking water-smart strategies to conservationists tracking ecosystem stress, the practical applications are as promising as the scientific questions are profound. In the hush above human hearing, nature is holding conversations we are only beginning to decode.