Amphitornus coloradus, commonly known as the striped slant-faced grasshopper, is a species of grasshopper belonging to the family Acrididae and the subfamily Gomphocerinae. It is native to the grasslands of North America, with a distribution ranging from the Canadian Prairies through the Great Plains and into the southwestern United States and Mexico.
Taxonomy and Morphology
The species was first described by Thomas in 1873. Amphitornus coloradus is characterized by its slender, medium-sized body, typically ranging from 20 to 30 millimeters in length. It possesses a distinctive slanted facial profile, a trait shared by many members of its subfamily. Its coloration is generally brownish or grayish-green, marked by two prominent dark longitudinal stripes that extend from behind the eyes, across the pronotum, and onto the tegmina (forewings). These stripes are often bordered by lighter, cream-colored lines, providing effective camouflage within its grassy habitat.
Habitat and Ecology
Amphitornus coloradus primarily inhabits shortgrass, mixed-grass, and desert prairies. It is a specialist feeder, classified as a graminivore, meaning its diet consists almost exclusively of grasses. It shows a documented preference for specific species such as needle-and-thread grass (Hesperostipa comata), blue grama (Bouteloua gracilis), and threadleaf sedge (Carex filifolia).
The species is univoltine, producing one generation per year. It overwinters in the egg stage, with embryonic development occurring in the soil. Nymphs typically emerge in late spring, and adults are most active from mid-summer through early autumn.
Economic Significance
While Amphitornus coloradus is a common inhabitant of western rangelands, it is generally not classified as a primary agricultural pest. However, during periods of high population density or "outbreaks," the species can contribute to the depletion of forage grasses available for livestock. Because of its specialized diet, its impact is largely confined to native grass species rather than cultivated crops. Management of the species is usually integrated into broader rangeland pest monitoring programs.
