Melanoplus differentialis (Thomas)

 
Adult male Adult female

Common name - Differential grasshopper (Hantsbarger, 1979)

Geographic distribution - can be found throughout the United States but is highly discontinuous in the far East and far West and seldom is found farther north than the southern borders of North Dakota and Minnesota (Froeschner, 1954; Parker, 1952). Found throughout eastern Colorado (Alexander, 1941; Bruner, 1897) and occasionally in western Colorado.

Colorado Distribution Map

Habitat - found on cultivated crops growing on low, moist ground and on plowed fields (Bruner, 1897).

Food habits - a mixed feeder preferring grasses. It also prefers rank growing, juicy foods such as corn, clover, alfalfa and various garden products. It frequently is found eating belvedere summercypress (Bruner, 1897; Mulkern et al., 1969).

Eggs - females have been known to deposit up to 156 eggs in one pod. Some pods contain 70 to 90 eggs and others as low as 36. It is likely that a single female makes three pods with about 250 total eggs. Eggs are olive colored, about 4.6 mm long and 1 mm in diameter. They are arranged in four columns within the pod (Carothers, 1924; Corkins,1921; Onsager and Mulkern, 1963).

Nymph - six instars (Shotwell, 1941).

Adult - large. General color is yellow to yellowish-brown with contrasting black markings; sometimes black. Tegmina are uniform. Wings are colorless. Outer face of hind femora has distinctive black bars arranged in a herringbone pattern. Dorsal posterior margin of pronotum is curved. Hind tibiae are yellow with black spines and a narrow black ring near the knee. These characteristics are less visible in a black morph. Cerci are distinctly boot-shaped; subgenital plate tapers to a point; furculae are very reduced. Male length, 30 mm; female, 40 mm (Blatchley, 1920; Hantsbarger, 1979).
 
Cercus Hind femur Hind femur (Black morph)

Oviposition - eggs are deposited in raised plant crowns of somewhat isolated clumps of sod. Common oviposition sites are compact roads, deserted fields, edges of weed patches and well-grazed areas near weedy ravines (Bruner, 1897; Shotwell, 1941).

Seasonal history - adults are common in the latter part of July. They deposit eggs from mid-August to October, and the eggs overwinter (Bruner, 1897; Corkins, 1921).

Abundance and importance - abundant and destructive in Colorado's lower elevations but has not been collected above 5,500 ft. Although it is a destructive pest of cultivated crops, it is of little importance in grasslands. It is sometimes a serious pest in suburban areas (Blatchley, 1920; Mulkern et al.,1969).

M. differentialis fact sheet from the Field Guide to Common Western Grasshoppers
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Biology of Common Colorado Grasshoppers
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