Insects Betray Themselves in Nature to Predators by Rapid Isomerization of Green Leaf Volatiles

Abstract

Plants' Modified SOS Call Plants have several ways of defending themselves against insect attack. The release of distinctive volatile chemicals betrays the location of herbivores to their predators, but volatile production can be slow and the pests may escape. Compounds known as green leaf volatiles are released immediately after damage, and Allmann and Baldwin (p. 1075 ) have found that, when attacked by tobacco hornworm ( Manduca sexta ) caterpillars, Nicotiana attenuata plants emit a compound that, when combined with an oral secretion from the caterpillar, is transformed into an attractant for the generalist hemipteran predator Geocoris pallidens , which preys on the hornworm eggs and young larvae. Thus, insect feeding activity can begin the process of plant defense before other protective volatiles are synthesized and emitted.