Orphulella speciosa

Distinguished from the similar Orphulella pelidna by structural features of the head and pronotum. O. speciosa has a small median ridge on the fastigium (the area between the eyes), with a small semicircular depression of the vertex located closer to the front; the lateral carinae of the pronotum are incised once. O. pelidna is larger, with a larger semicircular depression set farther back on the vertex, and the lateral carinae are incised twice (occasionally three times). The margins of the vertex are less raised than in related species, and the foveola (small integument dent) is not distinct. Pronotal disks are nearly equal in width front and back. The principal sulcus on the pronotum cuts the disk slightly past the middle.

Small, long-winged grasshopper with a strongly slanted face. Tegmina extend to the end of the hind femora and curve inward at the apex. Sexually dimorphic: females 16–21.5 mm in body length with antennae 5–6 mm, tegmina 9–16 mm, and hind femora 9.5–12 mm; males 13–14 mm in body length with antennae 4.5–6.5 mm, tegmina 10–13 mm, and hind femora 8.5–10 mm. Males' hind femora vary 1.5–3 mm from the end. Coloration highly variable: combinations of green, brown, and tan, usually spotted and marked with brown and black. Some individuals predominantly green, others entirely tan and brown. Females often light green with dark vertex; occasionally brown with lateral pronotal lines. Males have a pale curved line on the lower end of lateral pronotal lobes. Compound eyes tan with fuscous spots and markings. Behind each eye, a broad fuscous band, above it a thin black line, and above that a light line often ivory-colored.

Inhabits tallgrass and mixed-grass prairies, preferring areas of shorter grass interspersed throughout the prairie plant matrix, including grazed patches. Most abundant in upland areas of short grasses. In shortgrass prairie of Colorado and New Mexico, occupies mesic swales. In eastern states, occurs in relatively dry upland and hilly pastures with sandy loam soil. Generally prefers mesic habitats; center of distribution appears to be in the tallgrass prairie.

Occurs east of the Rocky Mountains to the Atlantic Coast, from southern Canada (northern extent of range) to northern Mexico (southern extent). Documented in Alabama, Arkansas, Colorado, Illinois, and Massachusetts. Widely distributed in North American grasslands.

Late-developing species. Hatching begins mid-to-late May in southern range (Flint Hills, Kansas at 1,200 ft elevation), early-to-mid June in northcentral Colorado (5,750 ft), and late June in eastern Montana. Hatching period extends 4–6 weeks. Nymphal development takes 42–48 days. Adults appear early July in Flint Hills, mid-July in Colorado, and early August in eastern Montana. Peak adult abundance: first or second week of August in Flint Hills; July–August in New England; August–October in Texas (southern range), with fewer adults present May–December.

General grass feeder, exhibiting some preferences among grass species. Feeds almost exclusively on grasses, usually in proportion to their availability. Documented food plants include blue grama, sideoats grama, Kentucky bluegrass, little bluestem, big bluestem, buffalograss, hairy grama, prairie junegrass, western wheatgrass, tall dropseed, sand dropseed, Leibig panic, Scribner panic, switchgrass panic, prairie sandreed, reed canarygrass, prairie threeawn, stinkgrass, yellow bristlegrass, Canada bluegrass, arrowfeather threeawn, and poverty oatgrass. Also consumes sedges (Penn sedge, needleleaf sedge, fieldclustered sedge). Unidentified fungi present in 6–8% of crops. Occasional forbs and arthropod parts detected. Feeds vertically head-up on leaf edges, consuming about 1/8 inch of leaf edge at a time, leaving thin residual edges standing.

Hemimetabolous (incomplete metamorphosis) with five nymphal instars. Eggs deposited in summer in pods measuring 13/16 inch long, containing 10–13 eggs each. Eggs 3.5–4.1 mm long, pale yellow when laid, becoming brown with age. Eggs overwinter and hatch the following late spring. One generation annually. Nymphs: Instar I–II with green head patterns, terminally expanded antennae (flat and pointed in II), tan hind femora, green thorax. Instars III–V with filiform antennae, tan/brown/green/gray body coloration, fuscous hind femora. Lateral abdominal band green in I–II, fuscous in III–V.

Phytophilous, resting on vegetation (principally grasses) day and night. At night, rests 2–3 inches high on stems and leaves of short grasses. After sunrise (~9 a.m.), climbs up to bask at 45° angle with dorsum and side in sun; basking lasts ~2 hours. Feeds when ground temperature reaches 85°F and air temperature 70°F. Flushed flight silent, straight or circular, 1–4 feet distance, usually 4–12 inches high (occasionally to 5 feet), chiefly crosswind. Courtship involves male stridulation (faint ticking sound, repeated 3–10 times); males stalk females slowly and pounce without signaling. Males stridulate after coupling to maintain pair bond. Pairs in copulo observed 9 a.m. to 2 p.m. Disperses widely using long wings; attracted to electric lights at night. Swarming behavior observed in New England. Populations disperse when food becomes scarce.

Primary consumer in grassland ecosystems. Often numerically dominant in tallgrass prairie assemblages, contributing significantly to grass herbivory. During outbreak conditions (e.g., 1934–1937 in western Iowa), assemblages with Ageneotettix deorum and other species destroyed all green vegetation in bluegrass pastures, reaching 30–100+ per square yard. Contributes to overall forage damage by grass-feeding grasshopper assemblages. Daily mortality rate approximately 9% for peak adults, 2% for late nymphal and early adult stages. Serves as prey for parasites and predators.

Economic pest in rangeland and pasture systems. Contributes to forage damage during population outbreaks, though individual consumption lower than larger species due to small size (adult males average 86 mg live weight, females 173 mg). During 1934–1937 outbreak in western Iowa, contributed to complete destruction of green vegetation in bluegrass pastures. Populations fluctuate, increasing during series of dry years. Because it feeds almost exclusively on grasses, contributes to cumulative damage of grass-feeding grasshopper assemblages. Managed as part of rangeland grasshopper control programs.

• Orphulella pelidnaOverlapping range and similar appearance, but larger with semicircular vertex depression set farther back and lateral pronotal carinae incised twice (vs. once in O. speciosa)

• grasshopper
• pasture pest
• prairie species
• North America
• grass feeder

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