Aeropedellus clavatus

The club-shaped antennae with six enlarged, dark terminal segments are diagnostic and give the species its common name. The hourglass-shaped constriction in the lateral pronotal carinae is characteristic of slant-faced grasshoppers but particularly notable here. The combination of slanted face, oblong lateral fovolae, and the distinctive head striping (dark streak from eye to mandible base with cream band anteriorly) separates it from similar species. Flightless females with short wings and white genal marks are distinctive. In nymphs, the grey medial hind femur with pale grey lower marginal area, combined with the head and pronotal patterns, allows identification.

Adults are medium-sized, 16–22 mm in length, with coloration ranging from light brown and grey to green, marked with black or silver patterns. The head has a strongly slanted face with two oblong lateral fovolae (indentations) on top. A dark streak runs from beneath the compound eye to the base of the mandible, with a cream or light tan band anterior to it. The pronotum has median and lateral carinae (ridges) cut by a groove behind the middle; the lateral carinae constrict near the middle of the prozona, forming an hourglass-shaped marking. A pale diagonal mark is often present on the vertical sides of the pronotum. The hind wing is clear, and the hind tibia is light brown. Females have short wings that do not reach the middle of the abdomen and white marks on the genae; males are smaller (16–18 mm vs. 19–22 mm) and may have long wings. Nymphs progress through four instars, with strongly slanted faces, oblong lateral fovolae, a narrow light stripe above a thick dark stripe running from behind the compound eye to the abdomen, and hind femurs with entirely grey medial areas and pale grey lower marginal areas. Male nymphs develop clavate antennae beginning at the second instar, while female nymphs retain flat antennae with little variation in width.

Northern mixed-grass prairies, mountain meadows, forested foothills, and alpine tundra above timberline. In the Canadian prairies, occurs on dry and somewhat sandy areas south of the boreal forest. One resident population survives above timberline at 13,600 feet in rocky, grass-sedge habitat in Colorado.

North America, from western Canada (prairie provinces: Alberta, Saskatchewan, Manitoba) through the northern United States (Montana, North Dakota, Nebraska, Wyoming) to the southwestern United States (mountains of Arizona and New Mexico). Most abundant and widely distributed grassland grasshopper species in the Canadian prairies.

Very early-hatching species; nymphs emerge in the first week of May in eastern Wyoming, about ten days before the bigheaded grasshopper. Hatching period lasts three to four weeks. In alpine areas above timberline in Colorado, hatching begins mid to late June depending on altitude and seasonal temperatures. Nymphal development completes in approximately 30 days on plains and 42 days in alpine habitats. Adults present from late spring through summer.

Primarily grasses and sedges, including western wheatgrass, prairie junegrass, Sandberg bluegrass, needle-and-thread, threadleaf sedge, and needleleaf sedge. Kentucky bluegrass (Poa pratensis) is a preferred host when available. Grass seeds and glumes are heavily consumed when available. Known to feed on at least 28 species of grasses and six species of sedges. Small amounts of forbs, fungi, pollen, and arthropod parts have been found in crop contents but appear incidental.

• Poa pratensis - preferred food plantmost favored food plant when present
• Pascopyrum smithii - food plantwestern wheatgrass
• Koeleria macrantha - food plantprairie junegrass
• Poa secunda - food plantSandberg bluegrass
• Hesperostipa comata - food plantneedle-and-thread
• Carex filifolia - food plantthreadleaf sedge
• Carex eleocharis - food plantneedleleaf sedge

One generation per year in plains habitats. Eggs are laid in pods of 5–8 in soil among roots of grasses or sedges; pods are 10–13 mm long, 3.5–4.0 mm in diameter, oriented vertically. Eggs develop rapidly to stage 26 (embryo nearly ready to hatch) then enter diapause for winter. In alpine habitats, eggs may remain in diapause for two or possibly three winters before hatching. Nymphs progress through four instars, developing rapidly to become adults in 30–42 days. Early hatching provides access to abundant green vegetation but exposes nymphs to intensive predation before later-hatching species emerge.

Adults generally remain in the same area where they hatched and developed. Long-winged males frequently fly for short periods and distances; some evidence suggests they may migrate. Adult males spend more time crawling on the ground than females, which move slowly and remain motionless for long periods. When threatened, females hop away from predators; males hop away then 'prance'—taking small, repeated hops without appreciable forward progression. Males stridulate by vibrating the hind femur against a raised vein on the tegmen, producing a loud scratching sound, probably for courtship.

Primary consumer feeding on grasses and sedges; serves as prey for birds, rodents, spiders, and predaceous insects. Early hatching phenology makes it particularly vulnerable to predation, with predators typically reducing densities to fewer than one per square yard by early summer. Its rapid development allows exploitation of high-quality forage before later-hatching competitors emerge.

Occasional pest of forage grasses and cereal grains. Not generally economically important, but dense populations (up to 20 per square yard on rangeland in Canada) can cause severe damage to forage grasses. Outbreak recorded in 1936 in Saskatchewan destroyed 300 acres of wheat. Frequently abundant in grasshopper assemblages infesting rangeland in Montana and North Dakota.

• Ageneotettix deorumBoth are early-hatching Gomphocerinae in similar habitats; A. deorum has white whisker-like markings on the face and lacks clubbed antennae
• Aulocara elliottiSimilar slant-faced grasshopper in same habitats; A. elliotti has a proportionally larger head and different pronotal markings
• Amphitornus coloradusStriped slant-faced grasshopper with similar body shape; A. coloradus has bold lateral stripes and thread-like antennae without clubbing
• Chorthippus curtipennisMeadow grasshopper with overlapping range; C. curtipennis has shorter wings relative to body and lacks the distinctive head markings and clubbed antennae

• grasshopper
• slant-faced
• early-hatching
• sexual dimorphism
• wing polymorphism
• prairie
• alpine
• pest
• Gomphocerinae

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Grasshoppers of Colorado
• Clubhorned Grasshopper
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Species Records and Accounts
• List of Species Fact Sheets| Grasshoppers of Wyoming and the West
• Life History of Aeropedellus clavatus (Orthoptera: Acrididae) in the Alpine Tundra of Colorado