Trimerotropis pallidipennis

Distinguished from other Trimerotropis species by the combination of: narrow black band on hindwing (broader in many congeners), two complete transverse dark bands on tegmen, black inner medial area of hind femur with two yellow bars, straight ventral edge of pronotal lobe without tooth, and yellow hind tibia. Nymphs are identifiable by triangular foveolae on the head, twice-incised median carina on pronotum, and characteristic color patterns: instar I has mainly black hindleg with pale basal fourth of femur; instars III-V have pale tan hind femur with two or three black bars and yellow hind tibia.

Adults are moderately-sized, tan to gray grasshoppers with distinct wing patterns. The tegmen (forewing) bears two transverse dark bands crossing its entire width, with numerous brown spots at the distal end. The hindwing has a relatively narrow but conspicuous black band across the center, with a white to pale yellow wing disk and transparent apical area. The pronotum has a median carina incised twice near the front—high on the prozona and low but distinct on the metazona—with a straight ventral edge bearing no tooth. The inner medial area of the hind femur is black, broken by two yellow bars. The hind tibia is yellow. The venter is solid cream to pale yellow. Live weight varies with environmental conditions: males average 175-268 mg, females 399-565 mg.

Primary habitats are desert and semi-desert rangelands of western North America, characterized by shrubs, forbs, and grasses with abundant bare ground for basking and resting. Vegetation includes annual grasses such as downy brome and needle grama, perennial grasses, and various forbs. Outside natural rangelands, populations establish in weedy city lots and disturbed areas. Habitats with succulent vegetation support faster reproductive maturation than dry desert sites.

Ranges from southwestern Canada (southern Alberta, Saskatchewan) through the western United States to Mexico, Central America, and South America to Argentina. In the United States, occurs in Washington, Oregon, California, Nevada, Arizona, Utah, Idaho, Montana, Wyoming, Colorado, New Mexico, and Texas. The most widely distributed bandwinged grasshopper in the New World. Introduced to Hawaii (Oahu) in 1966, where it persisted through 1968.

Hatching begins in late February to March in southern Arizona, late April in Utah, and May to June in Colorado and Wyoming. Nymphal development lasts 31-60 days depending on temperature. Adults appear mid-April in southern Arizona and early June in northern states. In southern Arizona, a second generation hatches in early June; northern areas have only one generation. Adults present from spring through summer, with some individuals surviving 67+ days in favorable habitats.

Polyphagous, feeding on a variety of forbs and grasses with diet shifting based on availability and quality. Early spring nymphs feed on lush annual grasses (downy brome, needle grama). As annual grasses dry, grasshoppers switch to green perennial grasses and forbs. Crop contents have revealed: downy brome (63% of crops), tumblemustard (22%), blue grama (23% in Texas), Cryptantha sp. (16%), and various wheatgrasses, rabbitbrush, milkvetch, and other forbs. Laboratory preferences include dandelion, kochia, downy brome, crested wheatgrass, and needleandthread.

Eggs are laid in bare soil to approximately 1 inch depth in slightly curved pods about 1 inch long and 1/8 inch in diameter, averaging 34 pale yellow eggs per pod. Eggs overwinter and enter diapause; hatching requires rainfall for survival. Under laboratory conditions (moist soil, 82-104°F), eggs can hatch in 13-21 days without diapause. Nymphs have 5-6 instars (females may have 6, males usually 5). Nymphal period ranges 31-60 days depending on temperature. Females average 386 eggs each; one recorded female laid 27 pods with 955 eggs. Preoviposition period averages 43 days (minimum 26 days). Female longevity averages 80 days in captivity.

Possesses strong flight capabilities for dispersal and migration. Flushed individuals fly swiftly at 2-3 feet height, often exceeding 100 feet. Prolonged flights can last 17+ minutes with individuals ascending out of sight; pilots have reported swarms at 3,000-5,000 feet altitude. Nocturnal flights occur, with swarms attracted to city lights. Males crepitate (produce snapping sounds with hindwings) during flight, which appears to initiate pair formation. Courtship involves stridulation producing trilling sounds, with 1-8 trills in quick succession. Average daily movement in Texas study was 27 feet, with 25% recapture rate indicating substantial emigration from study plots.

Primary consumer in desert and semi-desert ecosystems. During outbreak populations, can significantly reduce forage biomass and alter plant community composition. Serves as prey for various vertebrate and invertebrate predators. Population irruptions are associated with above-normal, well-distributed rainfall in fall, winter, and early spring, which provides favorable soil conditions for eggs and nutritious food plants for nymphs. Between outbreaks, populations remain rare for 3-4 years.

Significant agricultural pest during population irruptions. Outbreaks documented in Arizona (1952-1980: six outbreaks; 1998 most recent), California, New Mexico, and Utah. Damage recorded in wheat (defoliation, head cutting at 25-50 adults per square yard), cotton (seedling consumption to ground level at 5-10 per square yard), carrots, sugarbeets, barley, milo, corn, safflower, and grapes. Night flights to city lights create traffic hazards from crushed grasshoppers on roads; accumulations around buildings reached 2 inches depth in 1998 Arizona outbreak. Managed with insecticides and cultural practices.

• Trimerotropis cyaneipennisAlso has banded wings, but hindwing band is broader and body coloration differs; T. pallidipennis has narrower black hindwing band and yellow hind tibia.
• Trimerotropis cinctaSimilar bandwing pattern, but T. pallidipennis distinguished by specific hind femur pattern (black inner medial area with two yellow bars) and pronotal carina structure.
• Xanthippus corallipesShares subfamily Oedipodinae and bandwinged habit, but differs in body size, coloration, and hindwing pattern; T. pallidipennis is more slender with distinct tegmen banding.

• grasshopper
• pest
• desert
• bandwinged
• migratory
• agricultural pest
• western North America
• irruptive population
• polyphagous

• BugGuide
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Species Records and Accounts
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Pallidwinged Grasshopper