Aulocara

Members of Aulocara possess the characteristic slant-faced morphology of subfamily Gomphocerinae, with faces angled backward from the vertical plane. Aulocara elliotti is distinguished by a relatively large head, gray coloration with fuscous markings, and forewings with spotted patterns extending slightly beyond the abdomen. The pronotal disk typically displays light lines forming an X-pattern. Hind femora bear two black bars on the upper medial area, continuing onto the upper marginal area and inner medial area, with black knees. The hind tibia is medium blue. Aulocara femoratum (white-crossed grasshopper) differs in having two deep clefts on the posterior margin of the eighth abdominal sternum in adult females, versus the smooth margin in A. elliotti.

Species in this genus inhabit a variety of grassland types including desert grassland, mixed-grass prairie, shortgrass prairie, and bunchgrass prairie. They require open terrain with bare ground for basking, oviposition, and ground-foraging activities. Vegetation consists primarily of native grasses and sedges.

Western North America, ranging from southern Canada through the western United States to central Mexico. Documented in Colorado, Kansas, Montana, Nebraska, Wyoming, Arizona, and Mexico Northeast.

Early-hatching species with eggs beginning embryonic development in summer of deposition and reaching 50% development before winter diapause. Nymphs emerge in mid-spring when soil temperatures rise above 50°F, completing development in 36-42 days. Adults present from late spring through summer, with one generation annually.

Graminivorous. Aulocara elliotti feeds primarily on green leaves of grasses and sedges, including blue grama, western wheatgrass, needle-and-thread, thread-leaf sedge, and needleleaf sedge. Crested wheatgrass is a preferred introduced host. Also consumes ground litter including cut grass leaves, seeds, bran, and even dead grasshoppers. Documented to feed on at least 22 grass species and 2 sedge species.

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

Eggs laid in early summer at shallow depth (average 3/8 inch), enclosed in tough pods containing 7-9 eggs. Embryos develop to 50% completion before entering winter diapause. Diapause broken after exposure to 37-41°F for approximately 80 days. Hatching triggered by soil temperatures rising to 50°F and accumulation of 450 day-degrees (base 50°F). Nymphal development requires 36-42 days; males typically have 4 instars, females 5 instars. Adults live 20-72 days depending on conditions; females become receptive to mating at 6-8 days old and deposit first egg pods at 12-20 days old. Average fecundity 15-116 eggs per female under field conditions, up to 161 eggs in optimal laboratory conditions.

Ground-dwelling insects with activity strongly influenced by temperature and light. Daily routine includes basking perpendicular to sun rays one to two hours after sunrise, becoming active around 70°F air temperature and 95°F soil surface temperature. Engage in pottering (intermittent wandering with frequent direction changes), feeding, mating, and oviposition during active periods. When temperatures exceed 90°F air and 120°F soil, individuals stilt (raise bodies on legs) or move to shade. Resume activity as temperatures decline in afternoon, with evening basking two to three hours before sunset. Night spent resting uncovered on ground. Adults capable of evasive flight 2-7 feet at 4-12 inches height; evidence of longer dispersal movements up to 1-7 miles. Courtship involves visual cues with males approaching females and displaying by tipping hind femora and waving antennae. Copulation lasts 40-70 minutes. Females sweep soil over oviposition holes using hind tarsi as brushes.

Significant primary consumer in grassland ecosystems. High-density populations can substantially reduce grass biomass, altering vegetation structure and potentially exposing soil to erosion. Serves as prey for diverse predators including birds, rodents, beetles, and bee flies. Eggs experience 54% predation mortality between fall and spring. Subject to natural disease outbreaks including Nosema infections that can decimate populations.

Major economic pest of rangeland grasses in western North America. Aulocara elliotti often dominates outbreak assemblages, reaching densities of 20 per square yard in mixed-grass prairie and 40 per square yard in desert grassland. Individual consumption estimated at equivalent to 20 pounds dry forage per acre per grasshopper per year. Damage occurs through direct consumption and leaf-cutting behavior that drops forage to ground. Outbreaks can persist 5+ years, reducing livestock grazing value and promoting erosion. Subject to chemical control programs and integrated pest management using bait formulations.

• Amphitornus coloradusAlso a slant-faced grasshopper in Gomphocerinae with similar habitat preferences; distinguished by different color patterns and pronotal markings
• MelanoplusSpur-throated grasshoppers in different subfamily (Melanoplinae); distinguished by vertical face, presence of spur on prosternum, and different hind leg coloration
• AeropedellusSlant-faced grasshopper in same subfamily; Aulocara distinguished by larger head size in A. elliotti and distinctive pronotal X-pattern

• grasshopper
• rangeland pest
• graminivore
• western North America
• slant-faced
• economic pest

• BugGuide
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• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Bigheaded Grasshopper
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Grasshoppers of Colorado
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