ADAPTIVE RESPONSES OF GENERALIST HERBIVORES TO COMPETITION - CONVERGENCE OR DIVERGENCE

Generalist herbivores are often faced with a choice of eating abundant, low quality foods or rare high quality foods. An adaptive forger in this situation should have mixed responses (Abrams, 1990) to the densities of the two food types. Competition from another generalist herbivore species will generally cause convergence in foraging time allocations when both species are strictly food limited. Competition will usually cause a convergent response in traits determining the relative consumption rates of the two food categories. Divergent responses are possible when consumers are not strictly food limited. Divergent responses are also expected in some other traits related to resource use, such as gut size. Evidence for the predicted responses and implications for plant-herbivore coevolution are discussed. © 1990 Chapman and Hall Ltd.