“…The classic example is the outbreak of locust when the confluence of rains increases host plant abundance in space and time, and favorable winds occur that carry building locust populations from one favorable place to another until massive swarms occur (Roffey and Popov, 1968). Rapid buildups in response to host plant availability may occur in some species (e.g., cowpea aphid; Gutierrez et al (1974); and African armyworms, see Janssen (1993)), while in other cases outbreaks develop more slowly due to cyclic changes in host plants over time [e.g., spruce budworm (Thompson et al, 1979); bark beetles (Rebetez and Dobbertin, 2004); some vertebrate species (e.g., snowshoe hare/lynx, Krebs et al, 2002) and others]. The capacity to model such systems realistically is critical if we are to assess the impact of climate change on native and invasive species, but these require sound models of the plant dynamics.…”