Encoptolophus sordidus

Medium-sized, dark brown to greenish grasshopper with long wings extending 1–4 mm beyond abdomen tip. Tegmina banded; hind wings with weak to occasionally distinct apical dark bands. Fastigium distinctly longer than wide in males, slightly to distinctly longer than wide in females. Outer surface of hind femur with three dark bands (weak or absent in green specimens); hind tibia blue. Nymphs identifiable by moderately sloping pronotal disk (not tectate), clavate antennae in instars I–III becoming filiform in IV–V, and four distinct longitudinal ridges on outer faces of fore- and midleg femora and tibiae with black lines between ridges. Instar I with pink medial area of hind femur in distal half.

Native grasslands including mixedgrass, shortgrass, bunchgrass, and desert prairies. Most abundant in northern mixedgrass prairie. Favors moist areas with rich grass and sedge growth interspersed with bare ground; in southern distribution, occupies mesic swales and roadsides dominated by western wheatgrass, and prairies with heavy clay soils dominated by Texas needlegrass. Also inhabits fine sandy loam soils in mixedgrass prairie.

North America, ranging widely in western North America from Canada to Mexico. Documented in Colorado, Wyoming, Nebraska, Kansas, North Dakota, Saskatchewan, Texas, Arizona, and Pennsylvania.

Intermediate-developing species. Hatching begins early to mid June in northern mixedgrass prairie, continuing 6–8 weeks. Adults appear August 8–14 in Wyoming and Saskatchewan. In southern distribution (northeastern Texas), adults appear mid April with second generation by August, and juvenile stages present year-round with at least two generations annually.

Primarily grasses (Poaceae) and sedges (Cyperaceae). Principal host plants include western wheatgrass (Agropyron smithii), needleleaf sedge (Carex eleocharis), northern wheatgrass, needle-and-thread (Stipa comata), green needlegrass, and blue grama (Bouteloua gracilis). Additional consumed plants include quackgrass, prairie junegrass, sand dropseed, little bluestem, sideoats grama, Kentucky bluegrass, foxtail barley, and timothy. Forbs consumed sparingly in nature (approximately 1% of diet) but accepted when starved in laboratory; includes alfalfa, scarlet globemallow, prairie coneflower, dandelion, and Vicia sparsifolia.

Egg stage overwinters. Hatching intermediate in timing relative to other grasshoppers. Nymphal development requires five instars for both sexes, lasting 56–66 days in northern mixedgrass prairie. Adults sexually immature upon emergence; require 2–3 weeks growth and maturation before mating. Oviposition may begin by day 16 of adulthood. Females deposit 14–20 tan eggs per pod, 4.0–4.4 mm long, in slightly curved pods approximately 19 mm long. Preferred oviposition substrate is bare ground, particularly Houston black clay soil when available.

Geophilus species spending nearly all time on ground. Nocturnal resting horizontally on bare soil and litter, often under thin leaf canopy. Basking behavior: 1–2 hours after sunrise, individuals turn side perpendicular to sun and lower associated hindleg to expose abdomen for 2–3 hours. Males search for mates on ground; non-receptive females escape by flight. Males produce crepitation flights to arouse females, and single bursts of vibratory stridulation followed by ordinary stridulation pulses when pursuing potential mates. Males often attend ovipositing females but are kicked away. Feeding occurs during midday hours at ground temperatures 76–126°F. At extreme high temperatures (≥125°F), individuals seek partial shade, rest on grass elevated above ground, or climb onto litter facing sun to minimize body exposure. Dispersal by flight enabled by long wings and strong thoracic muscles; flushed flight softly crepitates, travels 3–9 feet at 3–12 inches height, usually straight with occasional terminal turn.

Grass-feeder in prairie grassland ecosystems. Usually subdominant member of grasshopper assemblages, occasionally becoming dominant species in favorable habitats (documented at 74% of population in some Saskatchewan sites). Selective grazing on preferred grasses and sedges may influence plant community composition. Population density typically low (approximately 2.5 young adults per square yard at peak), with estimated consumption of 1.5–2.4% of annual grass production. Serves as prey for avian and other predators.

Minor economic importance as rangeland species. Occasionally reported as minor pest in alfalfa (Arizona, North Dakota) and as pest in fall wheat (Nebraska), where adults migrated from depleted rangeland into adjacent crops. Susceptible to carbaryl-treated bran bait (67% mortality in field trials) and malathion ultra-low volume applications. Subject to cooperative grasshopper control programs in western United States when populations reach threatening densities.

• Chortophaga viridifasciataNymphs appear similar in early instars (I–III), both usually green and structurally similar. Distinguished by ensiform (not clavate) antennae, two distinct longitudinal ridges on fore- and midleg femora and tibiae (not four), and entirely green hind femur medial area in instar I (not pink in distal half). Instars IV–V separable by tectate (steep roof-like) pronotal disk with acute posterior angle in C. viridifasciata versus moderately sloping disk with obtuse posterior angle in E. sordidus.

• grasshopper
• Oedipodinae
• prairie
• rangeland
• grass-feeder
• North America
• sexual dimorphism
• ontogenetic dietary shift
• geophilus
• intermediate development

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Grasshoppers of Colorado
• Dusky Grasshopper
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Grasshoppers of Colorado
• Food preferences of the dusky grasshopper, Encoptolophus sordidus costalis (Scudder) (Orthoptera: Acrididae)