A duo of researchers from Cornell University, Professor Andre Kessler and Kimberly Morrell, Ph.D., found that when certain plants are attacked by pests, they emit chemical signals to both ward off the pest and warn neighboring plants.

Kessler and Morrell studied leaf beetle larvae and goldenrods. When the larvae begin to eat the plant, the chemical message emitted tells the insect that the plant is damaged and a poor source of food. When the chemicals reach nearby plants, it triggers them to produce the same chemical defense message for protection.

The researchers observed that the beetle larvae prefer undamaged plants to plants that emitted the chemical signal, whether they were damaged or not. In addition, exposure to the volatile organic compounds emitted by the damaged plants is all it takes for neighboring plants to send out the same signal.

Plant communication has been observed in at least 35 plant species within 16 families. The chemical messages sent out are thought to "limit herbivore loads by keeping herbivores on the move between host plants," according to the study, which was published in the journal Functional Ecology.

The study was funded by the Biogeochemistry and Environmental Biocomplexity Graduate Group at Cornell University and the National Science Foundation.