Aulocara elliotti

Adults distinguished from similar Aulocara femoratum (whitecrossed grasshopper) by: eighth abdominal sternum of female without deep clefts (A. femoratum has two deep clefts); forewings usually extend slightly beyond abdomen (A. femoratum wings typically do not reach abdomen end); generally darker, less contrasting coloration. Nymphs distinguished from A. femoratum by drab gray coloration with less contrasting markings versus lighter tan/cream background of A. femoratum. From other slant-faced grasshoppers: combination of large head, X-pattern on pronotum, blue hind tibia with black knee, and two black bars on hind femur.

Medium-sized grasshopper with a disproportionately large head and slightly slanted face. Adults typically colored gray with fuscous markings. Spotted forewings extend slightly beyond abdomen. Pronotum disk marked by distinctive light lines forming an X-pattern, though several pattern variants exist in populations. Hind femur with two black bars on upper medial area continuing onto upper marginal area and inner medial area; knee black. Hind tibia medium blue. Females larger than males: live weight 285-663 mg (average 476 mg) versus 131-230 mg (average 189 mg) for males.

Inhabits diverse grassland types across western North America including desert prairie, mixedgrass prairie, shortgrass prairie, and bunchgrass prairie. Most abundant in areas with mid grasses (western wheatgrass, needle-and-thread) and short grasses (blue grama). In mixedgrass prairie, prefers sites with abundant western wheatgrass and needle-and-thread. In desert grasslands of Arizona, associated with sparse vegetation on gravelly soils. Eggs laid in bare ground patches 1-6 square inches surrounded by short grass canopy.

Western North America from southern Canada (Alberta, Saskatchewan) through the Great Plains to central Mexico. Documented in U.S. states: Colorado, Montana, Nebraska, Oklahoma, Wyoming, Arizona, New Mexico, Texas, South Dakota, North Dakota, Idaho. Distribution includes 60% more area than congener A. femoratum. Center of distribution in Southwest's shortgrass and desert prairies; abundant throughout mixedgrass prairie of Montana and Wyoming.

Early-hatching species. Eggs begin embryonic development summer of deposition, reach 50% development before winter diapause. Hatching occurs mid-spring (mid-May to early June in northern mixedgrass prairie; earlier in Southwest). Nymphal development 36-42 days. Adults present from late June through August, occasionally into September. One generation annually.

Obligate grass feeder. Consumes green leaves of grasses and sedges, including blue grama, western wheatgrass, needle-and-thread, thread-leaf sedge, needleleaf sedge. Also feeds on crested wheatgrass (introduced forage). Known to feed on 22 grass species and 2 sedge species. Crop contents average 2.2 plant species per individual. Also consumes ground litter: cut grass leaves (green or dry), seeds, bran, dead grasshoppers. Feeding behavior includes climbing grass blades, turning head-down, chewing leaf at various distances from tip, frequently cutting leaf which drops to ground.

• blue grama - primary food plantBouteloua gracilis, heavily grazed when available
• western wheatgrass - primary food plantPascopyrum smithii, preferred nutritious host
• needle-and-thread - primary food plantHesperostipa comata
• thread-leaf sedge - food plantCarex filifolia
• needleleaf sedge - food plantCarex duriuscula
• crested wheatgrass - preferred introduced hostAgropyron cristatum, nutritious forage plant

Hemimetabolous development with egg, nymph, and adult stages. Eggs laid in curved pods 1/2-5/8 inch long, 3/16 inch diameter, with nippled cap, containing 7-9 pale yellow eggs 5.2-5.5 mm long. Eggs deposited at shallow depth (average 3/8 inch) in bare ground. Embryonic development begins summer of deposition, reaches 50% before winter diapause. Diapause broken by 80 days at 37-41°F. Hatching triggered by soil temperatures ≥50°F and 450 day-degrees heat accumulation. Nymphs emerge over 3-4 week period. Males develop through 4 instars, females through 5 instars. Adults mature in 6-8 days, mate, begin oviposition at 12-20 days. Average adult longevity 20 days in nature; 72 days in protected field cages. Fecundity: 15 eggs/female in nature, 76-161 eggs/female in cages depending on food quality.

Ground-dwelling, geophilous species. Nocturnal resting on bare ground without vegetation cover. Morning basking behavior: sits perpendicular to sun rays, lowers flexed hindleg to expose abdomen, hugs ground surface for ~1 hour beginning 1-2 hours after sunrise. Activity threshold approximately 70°F air temperature and 95°F soil surface temperature. Activities include pottering (intermittent wandering with frequent direction changes), feeding, mating, oviposition. Thermoregulatory behaviors include stilting (raising body on legs) at high temperatures, moving to shade of shrubs when soil exceeds 120°F. Mating involves visual courtship: male approaches quickly, tips hind femora, waves antennae silently; copulation lasts 40-70 minutes. Female oviposits in bare ground, sweeps soil over hole with hind tarsi for ~1 minute post-deposition.

Primary consumer and significant herbivore in grassland ecosystems. Reduces grass forage through direct consumption and leaf cutting; cut material becomes litter or food for ground-feeding insects. At outbreak densities (20-40 per square yard), can lay land bare causing wind and water erosion. Serves as prey for birds, rodents, and insect predators. Eggs subject to predation by birds, rodents, beetles, and bee flies (54% mortality fall to spring). Adults and nymphs preyed upon by generalist predators. Contributes to nutrient cycling through consumption and production of frass and cadavers.

Major economic pest of western North American rangelands. Destructive at densities as low as one individual per square yard; field cage tests demonstrate reduction of 20 pounds dry forage per acre at this density. Outbreaks reduce livestock grazing value and cause soil erosion. Subject to chemical control programs; carbaryl bait and bran baits used for management. Integrated with biological control using Nosema locustae. Preserved specimens found on Grasshopper Glacier, Montana, evidence of historical mass migrations. Studied as model organism for grasshopper population ecology, thermal biology, and rangeland pest management.

• Aulocara femoratumCongeneric whitecrossed grasshopper with overlapping distribution. Distinguished by female eighth sternum with two deep clefts (absent in A. elliotti), wings typically not reaching abdomen end, and lighter coloration with more contrasting markings.
• Amphitornus coloradusCo-occurring early-hatching slant-faced grasshopper. Distinguished by striped rather than spotted forewings, different pronotal pattern, and smaller head relative to body.
• Ageneotettix deorumCo-occurring early-hatching grasshopper of similar size. Distinguished by different color pattern, less prominent head, and preference for sandier habitats.

• grasshopper
• pest
• rangeland
• graminivore
• early-hatching
• North America
• economic importance

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bigheaded Grasshopper
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Little Spurthroated Grasshopper
• Whitecrossed Grasshopper
• Threebanded Grasshopper