| in Did You Know Facts
Some trees emit chemicals that attract enemies of their enemies.
Trees may appear helpless and passive, but they are far more intelligent than they appear. They can not only produce chemicals to combat leaf-eating insects, but some can also send chemical signals through the air, presumably warning nearby trees to prepare for an insect attack. According to research, when trees and other plants receive these signals, they become more resistant to insects. Airborne signals from trees can even transmit information outside of the plant kingdom. Some have been shown to attract predators and parasites that kill the insects, effectively allowing a besieged tree to call in reinforcements. Chemicals that attract other arthropods have gotten a lot of attention, but a 2013 study discovered that apple trees