Cordillacris

Distinguished from similar slant-faced grasshoppers by the crenulate (scalloped) brown stripe on each tegmen. The triangular brown stripe behind the compound eye and the cream-colored wedge on the lateral lobe are additional diagnostic characters. Nymphs have strongly slanted faces and distinctive color patterns with brown on the upper half of the lateral lobe and cream on the lower half. Differs from Cordillacris occipitalis in having more contrasting color patterns on the hind femur.

Small, slender grasshoppers with cream-colored bodies and brown markings. Adults have a wide, brown, crenulate or scalloped stripe on each tegmen. The subocular groove is edged posteriorly with a narrow brown stripe. A conspicuous triangular brown stripe is present on the side of the head behind each compound eye. The upper part of the lateral lobe is brown; the lower is cream-colored. An anterior cream-colored wedge runs nearly to the top of the lateral lobe. Hind tibiae are pale gray to yellowish with a distal dark annulus.

Shortgrass and desert prairies, heavily grazed upland sites of the mixedgrass prairie, and bunchgrass prairie extending to shrub-grass associations. Prefers short stands of grass with blue grama dominant and interspersed with bare ground. Does not inhabit tallgrass prairie or dense stands of mid grasses.

Western North America from the Great Plains westward to Nevada and California. Recorded in Arizona, California, Colorado, Nebraska, and Nevada.

Hatching occurs in mid-May in desert prairie of Arizona and first half of June in mixedgrass prairie of eastern Wyoming and shortgrass prairie of northcentral Colorado. Adults appear in July in northern mixedgrass and shortgrass prairies.

Grass feeder; C. crenulata preferentially feeds on blue grama (Bouteloua gracilis) when available, comprising over 96% of adult crop contents in some populations. Also observed feeding on threadleaf sedge, needleandthread grass, hairy grama, buffalograss, burrograss, and needleleaf sedge.

• Bouteloua gracilis - primary hostBlue grama; preferred food plant comprising majority of diet
• Carex filifolia - secondary hostThreadleaf sedge; fed upon in Montana

Eggs are laid in summer and develop to embryonic stage 18 by fall, then enter diapause. They overwinter in shallow soil cells in the top one-half inch of soil. Development resumes in spring. Nymphal period averages 36 days (range 30-43 days), requiring four instars (rarely five in some females). Females produce two to three eggs at a time without forming a protective pod; eggs are pale yellow and 5-5.5 mm long.

Spends night resting in crowns of blue grama grass or on ground litter under blue grama canopy. Morning basking involves two main orientations: perpendicular to sun with lowered hindleg, or diagonally on grass with back exposed. Normal activities include walking in short bouts or up to 6 feet without stopping, waving antennae, and shaking hindlegs when stopped. Evasive flights are straight, silent, 2-8 feet in distance, peak height approximately 6 inches, usually landing facing away from intruder. Courtship involves male tipping hindlegs, depressing antennae, producing single burst of stridulation, then advancing toward female.

Herbivore in grassland ecosystems; functions as a subdominant member of grasshopper assemblages, typically comprising 1-4% of outbreak populations in northern mixedgrass prairie. Occasionally reaches dominance with densities up to eight per square yard.

Minor economic pest on rangeland. Attacks green leaves of blue grama, a preferred livestock forage grass. Generally not a serious pest due to small size and low densities, but has caused considerable damage to threadleaf sedge in Montana and destroyed young grasses on newly seeded rangeland in Arizona. Live weight of 45-110 mg limits total damage potential.

• Cordillacris occipitalisSimilar size and habitat but differs in wing pattern (spot-winged vs. crenulate-winged) and hatches 3-4 weeks earlier
• Chorthippus curtipennisAnother slant-faced grasshopper in same subfamily but lacks diagnostic crenulate wing stripes and cream-colored wedge on lateral lobe

• grasshopper
• slant-faced
• western grasslands
• blue grama specialist
• rangeland pest

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Crenulatewinged Grasshopper
• Species Records and Accounts