The role of ducking stems in plant anti-herbivore defense and its exploitation by herbivorous insects

摘要

Abstract Goldenrod stems whose apices nod are shown to have architectural resistance against some herbivorous insects that attack terminal buds. In Japan and other regions, many other plant species including herbs, climbers, shrubs and trees have similar ducking stems during young developing stages. Several herbivorous insects that attack young shoots cause stems to droop, resulting in an appearance similar to ducking stems. Thus, I postulated that ducking stems of many plants may also function to deter some phytophagous insects in addition to preventing photoinhibition, and that insects, especially stem-borers that induce stem drooping, may achieve fitness gains by reducing predation, parasitism and attacks on infested stems by other herbivores. Alternative mechanisms causing stem-ducking and experimental tests of the hypotheses and future directions are discussed.