Anabrus simplex (Haldeman)

 
Adult male Adult female

Common name - Mormon cricket (Anderson, 1941).

Geographic distribution - west of the Missouri River to the Cascade and Sierra Nevada ranges and from the Canadian border south to California and northern Arizona (Swan and Papp, 1972). In Colorado, A. simplex can be found from the eastern plains to the mountains above timberline (Hebard, 1929).

Colorado Distribution Map

Habitat - grassy areas, usually in brush (Hebard, 1928).

Food habits - feeds on over 250 species, mostly range plants but also cultivated crops. It prefers the flower and seed parts of plants and is often cannibalistic (Swan and Papp, 1972; Wakeland, 1952).

Eggs - color, dark brown turning grey. Eggs are 7 mm long and crescent shaped. They are deposited singly, but as many as 100 eggs may be closely grouped (Corkins, 1923; Swan and Papp, 1972).

Nymph - seven instars. Color black with white markings on pronotum (Ramsay, 1964; Swan and Papp 1972).

Adult - stout bodied. General color is brown, yellowish, green or black. Sometimes irregularly mottled or distinctly marked. A. simplex is wingless. In the male the tegmina extend a little beyond the pronotum and are used for chirping. In the female the tegmina are concealed by the pronotum. Females have a sword-like ovipositor curved upward. Head is large. Antennae are longer than body. Length, 24 to 62 mm (Helfer, 1972; Swan and Papp, 1972).

Oviposition - barren slopes and open spots among sagebrush, fields and along roads are common oviposition sites. Oviposition commonly takes place in the early morning, late afternoon or on cloudy days. Eggs are deposited just below the soil surface in firm but not hard soil, free from roots (Corkins, 1923; Swan and Papp, 1972).

Seasonal history - eggs are deposited in mid-summer. They overwinter and hatch the following spring. Adults appear in late June and early July (Swan and Papp, 1972).

Abundance and importance - in Colorado A. simplex is most common in the northwestern part of the state. Bands migrate on foot, moving up to a mile a day. They do their greatest damage to range forage (Anderson, 1941; Swan and Papp, 1972; Wakeland, 1952).

A. simplex fact sheet from the Field Guide to Common Western Grasshoppers
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Biology of Common Colorado Grasshoppers
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