The degree of adaptation to disturbance affects the predisposition of individuals to disperse. Species characterizing relatively stable, infrequently disturbed habitats tend to disperse slowly (i.e., produce few offspring and move short distances; see Chapter 5). Infrequent disturbance and consistent resource availability provide little or no selection for greater dispersal ability. Many forest species (especially Lepidoptera and Coleoptera) are flightless, or at least poor fliers. By contrast, species (such as aphids) that characterize temporary, frequently disturbed habitats produce large numbers of individuals and a high proportion of dispersers. Such traits are important adaptations for species exploiting temporary, unstable conditions (Janzen 1977).
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