The adaptation of insects to plant protease inhibitors

Plants and herbivores have been co-evolving for thousands of years, and as a result, plants have defence mechanisms that offer protection against many herbivores such as nematodes, insects, birds and mammals, Only when a herbivore has managed td adapt to these defence mechanisms does it have the potential to become a pest. One such method of plant defence involves the production of protease inhibitors (PIs), These-inhibitors are proteins that may be found constitutively in various parts of the plant, or may be induced in response to herbivore attack. PIs work at the gut level, by inhibiting the digestion of plant protein, This review focuses on insect herbivores and looks at the mechanisms involved in the role and function of PIs in plant defense against insects, as well as at the ability of well adapted species to overcome the effects-of these plant PIs. (C) 1997 Elsevier Science Ltd. All rights reserved.