Eritettix simplex

Distinguished from similar slant-faced grasshoppers by the combination of three head carinae, three pronotal carinae with white/cream lateral carinae that are cut once and moderately constricted near middle, and the distinctive velvet-like dark bands along the pronotal lateral carinae. Nymphs identifiable by strongly slanted face with pointed fastigium, three head carinae with lateral brown bands continuing on thorax and abdomen, and broad flat antennae. Early instars have unicolored pale tan or brown-striped hind femora; instars IV-V show distinct dorsal brown and ventral pale tan femoral stripes.

Primarily tallgrass prairie in the Great Plains, achieving highest densities there. Occupies mid and tall grass stands with blue grama understory. Extends into desert, mixedgrass, shortgrass, and bunchgrass prairies by occupying mesic swales and drainages. In the West, restricted to moist or humid microhabitats due to physiological sensitivity to dry air.

North America: two main centers—Great Plains of western North America (larger) and Appalachian Mountains with eastern slopes (smaller). Found from Canada through the United States to Central America. Specific records from Colorado, Delaware, Georgia, Illinois, Kansas, Wyoming, Montana, North Dakota, and Nebraska.

Late-hatching species. Hatching begins latter part of July in mixedgrass prairie at 4,000-5,000 feet elevation, continuing for about one month. Nymphs develop through summer and fall, overwinter in third-fourth instars under ground litter, complete development following spring (April-May). Adults peak in May, declining to sparse densities by July.

Specialist feeder on grasses and sedges. Early spring nymphs feed on cool-season plants: bluegrasses, downy brome, junegrass, threadleaf sedge, needleleaf sedge. Diet shifts to warm-season plants as season progresses, particularly blue grama, which is highly preferred and often sole food of adults. Other substantial foods include hairy grama, sideoats grama, sand dropseed, needleandthread. Summer and fall nymphs feed almost exclusively on blue grama. Twenty-five grass species and three sedge species recorded as eaten.

• blue grama - preferred food plantoften sole food of adults; summer and fall nymphs feed almost exclusively on this species
• Bouteloua gracilis - preferred food plant
• Poa spp. - foodbluegrasses; early spring food
• Bromus tectorum - fooddowny brome; early spring food
• Koeleria macrantha - foodjunegrass; early spring food
• Carex filifolia - foodthreadleaf sedge; early spring food
• Carex duriuscula - foodneedleleaf sedge; early spring food
• Bouteloua hirsuta - foodhairy grama
• Bouteloua curtipendula - foodsideoats grama
• Sporobolus cryptandrus - foodsand dropseed
• Hesperostipa comata - foodneedleandthread

Egg stage: eggs pale yellow, 4.4 mm long, laid in fragile pods approximately 1 inch long and 1/8 inch diameter, clusters of about 18 eggs. Oviposition into bare ground. Nymphal stage: late-hatching (July), develop through summer and fall for approximately 100 days, overwinter as third-fourth instars under ground litter, complete development following spring (April-May). Nymphal period lasts approximately nine months due to slow fall growth and winter dormancy. Adult stage: appear spring, peak May, decline by July. Life cycle duration (one-year or two-year) unknown; no thorough study completed.

Feeding: normally rests head-up on plant, either leaning and raising on hindlegs to attack plant about 1 inch above ground, or jumps/climbs to attack leaf middle. Cuts narrow leaves, holds detached section with front tarsi, feeds toward tip. May turn head-down to feed on leaf base. Flight: silent, straight, usually 2-6 feet at 4-12 inches height; lands horizontally with head pointing in flight direction away from intruder. Occasionally turns to face intruder after landing. Thermoregulation: nymphs and adults bask in morning sun, exposing side or back perpendicular to rays; nymphs use postures with flexed hindlegs positioned to maximize exposure. Take shelter under ground litter at night. Mating: male follows female, rocks side to side when within one inch, stridulates with one hindleg at a time by rubbing femur inside against raised tegminal vein, then rushes forward to mount. Cold tolerance: nymphs survive freezing and temperatures to -15°C.

Herbivore in grassland ecosystems. Potentially damaging pest of rangeland due to grass/sedge specialization, though typically at low densities. Population dynamics studied as component of grasshopper community competition and fluctuation in prairie ecosystems. Serves as prey base for grassland predators.

Economic: potentially damaging rangeland pest due to grass/sedge diet, but densities usually below one per square yard render populations innocuous. High densities recorded only in Sheyenne National Grasslands, North Dakota sand prairie (peaked at ~7 per square yard in 1960). Spring development timing means range plants usually have adequate moisture, reducing damage potential. Research subject for grasshopper population ecology, cold hardiness, and dispersal studies.

• Mermiria bivittataAlso slant-faced grasshopper in same subfamily; differs in having two light stripes rather than velvet bands, and different head carinae pattern
• Cordillacris occipitalisSlant-faced relative with spotted wings rather than striped pronotum, and different pronotal carinae structure
• Amphitornus coloradusAnother slant-faced grasshopper with striped pattern, but has different pronotal shape and carinae arrangement

• grasshopper
• slant-faced
• prairie
• blue grama
• late-hatching
• cold-hardy
• velvet-striped
• rangeland
• Gomphocerinae
• Great Plains
• Appalachian
• overwintering nymphs

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• List of Species Fact Sheets| Grasshoppers of Wyoming and the West
• Velvetstriped Grasshopper
• Species Records and Accounts