The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth

by Zoë Schlanger

At the time of my visit, Finnish evolutionary ecologist Aino Kalske, Japanese chemical ecologist Kaori Shiojiri, and Cornell chemical ecologist André Kessler had recently found that goldenrods that live in peaceful areas without much threat from predators will issue chemical alarm calls that are incredibly specific—decipherable only to their close kin—on the rare occasion they are attacked. But goldenrods in more hostile territory signal to their neighbors using chemical phrases easily understood by all the goldenrod in the area, not just their biological kin. Instead of using coded whisper networks, these goldenrod broadcast the threat over loudspeaker, so to speak. It is the first time research has confirmed that these sort of chemical communications are beneficial not only to the plant receiving them but also to the sender.* When times are truly tough, you don’t want to be left standing in a field alone when it’s over, if you’re a plant. There’ll be no one to mate with, no one to help bring in pollinators. It’s the closest scientists have come to showing intentionality in plant communication: these are signals meant to be heard. And as we know, by some measures, intention is an indicator of intelligent behavior.