Effects of Plant Epicuticular Lipids on Insect Herbivores

Abstract

The primary role of epicuticular lipids on aerial plant surfaces is prevention of water loss, but their species-specific chemical composition and their vari­ able crystal morphology suggest other ecological functions. Among these functions is mediation of interactions between plants and insect herbivores. Epicuticular lipid extracts and individual lipid components enhance or deter oviposition, movement, and feeding. The physical structure of plant surface lipids can affect insect herbivore attachment and locomotion. Surface lipids may also affect herbivores indirectly by influencing predatory and parasitic insects. Glossy crop phenotypes are often less susceptible to insect herbivores than are normal phenotypes. The epicuticular lipids of glossy plants are usually reduced in amount and have dramatically different chemical compo­ sition and morphology. Study of the basis of the reduced suscept ibility of glossy plants can help elucidate the role of plant surface lipids in insect-plant interactions.