Orphulella

Members of Orphulella possess a strongly slanted face, a diagnostic feature of the genus. The vertex typically bears a semicircular depression whose position relative to the fastigium varies among species. Antennae are filiform. Compound eyes are tan with fuscous spots and markings. Coloration is highly variable, ranging from green through tan and brown, often with spots and dark markings. Some species exhibit polymorphism with individuals bearing much green while others are entirely tan and brown. Species-level identification requires examination of structural characters: the position of the semicircular depression on the vertex (closer to front versus farther back) and the number of incisions on the lateral carinae of the pronotum (once versus twice or thrice).

Species inhabit North American grasslands from east of the Rocky Mountains to the Atlantic Coast. Most abundant in upland areas of short grasses in tallgrass and southern mixedgrass prairies. In shortgrass prairie regions, inhabits mesic swales. Generally prefers mesic habitats with center of distribution in tallgrass prairie. In eastern states, occurs principally in relatively dry upland and hilly pastures with sandy loam soil.

Widely distributed across North America from southern Canada to northern Mexico, and throughout the Americas including South America. Ranges from east of the Rocky Mountains to the Atlantic Coast. Specific distribution records include: northeastern United States, Alabama, Arizona, Caribbean, and Argentina Northeast.

Late-developing species with hatching beginning in mid-to-late May at lower elevations and continuing into June at higher elevations. Hatching period extends four to six weeks. Adults first appear in early to mid-July at lower elevations, mid-July to early August at higher elevations. Peak abundance occurs in August. Eggs are deposited in summer, overwinter, and hatch the following spring.

General grass feeders exhibiting some preferences among grass species. Feeds on grasses in proportion to their availability. Documented host 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 including Penn sedge, needleleaf sedge, and fieldclustered sedge. Small amounts of forbs, fungi, and arthropod parts detected in crop contents.

Eggs are deposited in summer in pods measuring approximately 13/16 inch long, containing 10-13 eggs each. Eggs are pale yellow when laid, becoming brown with age. Eggs overwinter and hatch the following year in late spring. Nymphs develop through five instars over 42-48 days from first hatch to first adults. Adults mature, mate, and reproduce in favorable habitats, persisting generation after generation with population fluctuations.

Phytophilous insect preferring to rest on vegetation day and night. At night, rests 2-3 inches high on stems and leaves of short grasses. Approximately two hours after sunrise, climbs grass stems and basks at 45° angle with dorsum and side in sun. Basking may last two hours. Feeds vertically, head-up on leaf edges, moving upward and consuming approximately 1/8 inch of leaf edge at a time, leaving thin residual edges. Occasionally feeds head-down. Males court females by stridulating with faint ticking sound repeated 3-10 times, or stalk moving females slowly and pounce without signaling. Pairs in copulo observed throughout daylight hours. Flushed flight is silent, often straight but sometimes circular, for 1-4 feet at heights of 4-12 inches, occasionally to 5 feet. Flights chiefly crosswind. Possesses long wings allowing wide dispersal; attracted to electric lights at night indicating nocturnal dispersal behavior.

Characteristic and frequently numerically dominant species in tallgrass prairie grasshopper assemblages. Contributes to overall damage of forage by grass-feeding grasshopper assemblages. During outbreak years, populations can reach 30-100+ individuals per square yard, consuming all green vegetation. Daily adult mortality rate approximately 9 percent during peak abundance, 2 percent for late nymphal and early adult stages.

Economic pest of pasture and rangeland grasslands. During drought-induced outbreaks, contributes to destruction of forage vegetation in concert with other grass-feeding grasshoppers. Documented to have destroyed all green vegetation in bluegrass pastures during 1934-1937 outbreak in western Iowa. Damage potential reduced relative to larger grasshopper species due to smaller body size (adult females average 173 mg live weight, males 86 mg).

• OrphulaFormerly confused with Orphulella; Orphula in the strict sense is not represented in the United States. Orphulella was separated from Orphula by Giglio-Tos in 1894 based on structural differences.
• Orphulella pelidnaOverlapping distribution with O. speciosa; distinguished by larger body size, larger semicircular depression of vertex set farther back, and lateral carinae of pronotum incised twice (occasionally three times) versus once in O. speciosa.

• grasshopper
• Acrididae
• Gomphocerinae
• Orphulellini
• grassland
• prairie
• pest
• North America
• polymorphism
• slant-faced

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Species Records and Accounts
• Grasshoppers of Colorado
• Slantfaced Pasture Grasshopper
• List of Species Fact Sheets| Grasshoppers of Wyoming and the West
• THE NORTH AMERICAN SPECIES OF ORPHULELLA
• Male reproductive tract and spermatozoa ultrastructure in the grasshopper Orphulella punctata (De Geer, 1773) (Insecta, Orthoptera, Caelifera)