Soil fungi, like the kind ragwort plants grow in, provide the perfect medium for inter- and intra-species communication. Insects, the researchers found, alter the chemical composition of soil surrounding any plant they so choose to feed on. Plants growing nearby pick up on these chemical changes and alter their own structure, accordingly. Insects who land on these neighboring plants pick up and continue to pass on these signals.
How long these messages last is still a question that study author Olga Kostenko and colleagues are seeking to answer. But she's pretty sure "plants are actually decoding a 'voicemail' message from the past to the next generation of plant-feeding insects, and their enemies."