Mermiria bivittata maculipennis

Distinguished from congeners by: 1) pronotal disk rounding off onto lateral lobe without lateral carinae; 2) pronotal disk margin cut by three sulci; 3) absence of ivory stripes on sides of occiput and pronotal disk; and 4) presence of one longitudinal white or ivory streak on tegmen. Mermiria texana has ivory stripes on occiput and pronotal disk and two white streaks on tegmen. Mermiria picta lacks ivory stripes and tegmen streaks entirely, and has well-developed lateral carinae on pronotal disk cut by two posterior sulci. Nymphs identifiable by strongly slanted face, triangular lateral foveolae invisible from above, and narrow brown band along side of head continuing on dorsal edge of lateral lobe.

Primarily tallgrass prairie, specifically habitats dominated by big bluestem (Andropogon gerardii), yellow indiangrass (Sorghastrum nutans), and switchgrass (Panicum virgatum). Frequently inhabits these grasses on slopes and hills. Also occurs in small edaphic stands of tall grasses within mixedgrass, shortgrass, bunchgrass, and desert prairies, as well as luxuriant stands of midgrasses in mixedgrass prairie. Requires bare ground nearby for oviposition.

Widely distributed in North America with center of distribution in the tallgrass prairie. Eastern Kansas, western Nebraska, northeastern Texas, eastern Wyoming. Extends into mixedgrass and shortgrass prairie regions through small edaphic tall grass stands. Not found in mountains west of Boulder, Colorado despite presence in adjacent plains and foothills.

Late-hatching species. First instars appear early May in tallgrass prairie of eastern Kansas; early to mid June in mixedgrass prairie of eastern Wyoming. Hatching period lasts two weeks or longer. Adults present from mid-summer through fall.

Obligate grass-feeder. Documented feeding on 18 grass species plus threadleaf sedge (Carex filifolia). Primary hosts include big bluestem, little bluestem, sand bluestem, yellow indiangrass, sideoats grama, tall dropseed, prairie sandreed, western wheatgrass, silver beardgrass, prairie dropseed, blue grama, downy brome, smooth brome, sand dropseed, needleandthread, and hairy grama. Caged preference tests showed selection of Bermuda grass and prairie dropseed over big bluestem and silver beardgrass. Feeds on green leaves, cutting sections 1-2 inches long and consuming from edge to midrib or entire sections of narrow leaves.

• Andropogon gerardii - primary hostbig bluestem
• Sorghastrum nutans - primary hostyellow indiangrass
• Panicum virgatum - primary hostswitchgrass
• Andropogon hallii - hostsand bluestem
• Schizachyrium scoparium - hostlittle bluestem
• Bouteloua curtipendula - hostsideoats grama
• Sporobolus composus - hosttall dropseed
• Calamovilfa longifolia - hostprairie sandreed
• Pascopyrum smithii - hostwestern wheatgrass
• Bothriochloa saccharoides - hostsilver beardgrass
• Sporobolus heterolepis - preferred hostprairie dropseed; preferred in caged tests
• Bouteloua gracilis - hostblue grama
• Bromus tectorum - hostdowny brome
• Bromus inermis - hostsmooth brome
• Sporobolus cryptandrus - hostsand dropseed
• Hesperostipa comata - hostneedleandthread
• Bouteloua hirsuta - hosthairy grama
• Cynodon dactylon - preferred hostBermuda grass; preferred in caged tests
• Carex filifolia - hostthreadleaf sedge; only non-grass host documented

Eggs deposited in bare ground near host plants at depths of 1.25-1.75 inches. Egg mass contains 14-18 eggs with no pod wall; eggs held together by spots of froth. Eggs tan or two-toned tan and yellow, 7.2 mm long. Long froth plug of 1.25 inches above eggs. Minimum nymphal period 40 days for males. Females have five instars, males have four. Late-hatching species with extended hatching period of two weeks or more. Slow nymphal development attributed to cooler temperatures in luxuriant grass habitat and above-ground location on tall grass.

Phytophilous species spending most of time perched on grass. Rests vertically head-up on leaves or culms at heights of 8-12 inches at night. Basks for 2-4 hours after sunrise by adjusting position to receive radiant heat on one side. Descends from perches by backing down, crawls onto other leaves, or jumps between plants. If landing on ground, immediately crawls up nearby grass. Preens antennae and compound eyes frequently. Moves to shady side of grass plants during high temperatures. Quiescent from approximately 8:30 p.m. to 7 a.m.; rain and cool temperatures extend quiescence. Strong, adept flyer with silent flight 2-12 feet at heights of 9-36 inches when flushed. Flight may be straight or sinuous. Takes off from vegetation, usually lands on vegetation but may land on litter or bare ground. Able to turn at end of flight to land vertically on upright culm, or veer to land within vegetated areas.

Primary consumer in tallgrass prairie ecosystems. Functions as a grass-feeder contributing to nutrient cycling through herbivory and leaf litter production. In tallgrass prairie, cut leaves often remain uneaten and become ground litter. Studies indicate limited impact on above-ground biomass even at densities of 5-11 grasshoppers per square yard. Fire-maintained grass habitats favor this graminivorous species over forb- or mixed-feeders by reducing competition from forbs and shrubs.

Potential pest of forage grasses in tallgrass prairie. Reaches outbreak densities occasionally (e.g., eastern Kansas 1939). Individual consumption estimated at 3.4 gm dry weight of grass per lifetime, exceeding that of Aulocara elliotti (2.0 gm). Rarely becomes significant pest due to generally low densities (typically under one adult per square yard) and abundant grass production in tallgrass prairie. Quantitative studies showed no significant difference in above-ground vegetation biomass between plots with 5 versus 11 grasshoppers per square yard. Large size makes it conspicuous but economic impact usually minor.

• Mermiria texanaOverlaps geographically and seasonally in the West; distinguished by ivory stripes on sides of occiput and pronotal disk, and two longitudinal white streaks on tegmen (one above base of hindleg, one above abdomen) versus one streak in M. bivittata.
• Mermiria pictaOverlaps geographically and seasonally in the West; lacks ivory stripes on occiput and pronotal disk and lacks tegmen streaks entirely; has well-developed lateral carinae on pronotal disk cut by two posterior sulci.
• Mermiria intertextaDistributed in eastern United States along Atlantic and Gulf coasts; not overlapping with western subspecies maculipennis.

• grasshopper
• tallgrass prairie
• grass-feeder
• late-hatching
• phytophilous
• slant-faced
• North America
• pest potential
• subspecies

• BugGuide
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• Grasshoppers of Colorado
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• Twostriped Slantfaced Grasshopper
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