Phase-polymorphism
Guides
Melanoplus differentialis
Differential Grasshopper
Melanoplus differentialis is a large, highly mobile grasshopper native to North America that has expanded from wet meadows into agricultural landscapes. It is a severe crop pest, particularly damaging to corn, alfalfa, soybeans, cotton, and small grains, with dense swarms capable of destroying young cornfields in three to four days. The species exhibits phase polymorphism, with crowded individuals developing darker pigmentation and different body proportions compared to isolated individuals. It has one generation annually and is better adapted to warmer climates than related species, with outbreaks concentrated in the central United States between the Rocky Mountains and Mississippi River.
Schistocerca
bird grasshoppers, bird locusts
Schistocerca is a genus of large grasshoppers commonly known as bird grasshoppers, with approximately 50 described species. The genus is notable for containing several species capable of forming destructive locust swarms, most famously the desert locust (S. gregaria), the only Old World representative. Most species occur in the New World, with ten species documented in North America. The genus exhibits phenotypic plasticity, with some species developing migratory morphs under crowded conditions.