Species Anabrus simplex - Mormon Cricket

Anabrus simplex Haldeman, 1852

Common name refers to invasion of agricultural lands farmed by Mormon settlers in the Great Salt Lake Basin in the 19th century, especially an outbreak in 1848 (Hartley, 2011).

28-45 mm (1)

western United States and adjacent southern Canada: s. Manitoba, Dakotas, Nebraska, Colorado, n. New Mexico west to British Columbia, Washington, Oregon, California (1).

Status of records of Anabrus simplex (in a museum collection) said to be from eastern Tennessee is unclear--that would be a 1,000 mile (1,600 km) extension of the range (Goodwin and Powders, 1970). It does not seem the species is found there currently. (Perhaps a mislabeling of location in museum specimens?)

open habitats, usually with little vegetation

June-September (adults)

Eggs may lay dormant in soil for a number of years, and then many may hatch in an area in the same season when conditions are ideal. Eggs hatch in spring when soil becomes warm enough, with adults often present by as early as late May (depending upon local conditions), and usually most abundant as adults in June and July. Most are generally gone by sometime in August or September, but some may live until the first freezes of autumn. If swarming occurs, it is usually most prominent early in the season, made up of nymphs and/or young adults. Later in the season (usually by August) swarms tend to break up, and older adults tend to become more sedentary. However, timing may vary a great deal from place to place and year to year, depending upon weather conditions.

Though flightless, this species can form migratory swarms or "bands" that travel on foot, eating almost anything (both plant and sometimes small animal) in their paths, and have been significantly destructive to rangeland and crops at times. Swarming occurs primarily in the Wyoming Basin, Colorado Plateaus, Great Basin, and Columbia Plateau. In the Sierras, Rockies, and other higher mountain areas, and on the northern Great Plains, individuals average smaller, are usually non-migratory, and coloring is commonly of lighter colors (often tan or green). Individuals in bands are most commonly of a deep brown, often nearly black color.