Food Plant Specialization and Environmental Predictability in Lepidoptera

The expectation that the niche breadth of species in relatively unpredictable environments should be greater than that of comparable species in more reliable environments is violated by the larval feeding habits of temperate zone Macrolepidoptera. Species that feed primarily on herbaceous plants are more often restricted to a single plant family than are species which eat the leaves of trees or shrubs. This pattern appears attributable to the coevolution of oviposition preferences with the evolution of plant defense systems, which probably tend toward greater diversity in floristically diverse plant communities and toward uniformity in less diverse communities.