Calling for Backup

When caterpillars chew corn leaves, the damaged plant releases a specific blend of volatile chemicals that attracts parasitic wasps. These wasps lay eggs inside the caterpillars, killing them from within. The plant essentially calls an air strike on its attackers.

Different herbivores trigger different chemical blends. Plants can distinguish between caterpillar saliva and beetle chewing by the specific enzymes in each attacker's saliva. They tailor their defense signals to recruit the right predator for each specific pest.