Melanoplus alpinus Scudder
Link directly to photos of adults, nymphs,
Distribution and Habitat
M. alpinus continental distribution map
Wyoming distribution map
The geographic range of the alpine grasshopper is located in northwestern
North America. It inhabits the grass-forb meadows and parklands of the
Rocky Mountains and the Sierra Nevada Mountains. In the United States,
altitudes of its habitats range from 6,400 feet in Montana to 11,000 feet
in Colorado. In Canada, the species lives not only in mountain meadows
and parklands but also in foothill habitats as low as 3,200 feet.
The alpine grasshopper, a common resident of mountain meadows, has a history
of low densities and no documented outbreaks. Researchers of the species
consider it to be a minor pest during some years and often a beneficial
insect due to its feeding on competing weeds and poisonous plants such
as locoweed and lupine. Populations in Wyoming meadows have ranged in density
from less than 0.1 to 3.7 adults per square yard. Because the alpine grasshopper
feeds readily on Idaho fescue, it is considered a potentially competitive
pest with livestock on summer range, particularly during droughts when
forage is in short supply.
The alpine grasshopper feeds on both forbs and grasses, and will eat fungi
and injured or dead arthropods. About 26 species of forbs, 11 grasses,
and 2 sedges are known to be ingested. Preferred forbs include Arenaria
congesta, Arenaria fendleri, Astragalus adsurgens, Lupinus
laxiflorus, Oxytropis campestris, Musineon tenuifolium,
and Taraxacum laevigatum. Preferred grasses include Poa spp.,
Elymus lanceolatus, Festuca idahoensis, and Stipa occidentalis.
Over its geographic range the alpine grasshopper subsists on different
diets. In Canada it is reported to feed on grasses. In Idaho, crop content
examinations show it to feed evenly on forbs and grasses; in Colorado,
69 percent of its diet is forbs and 18 percent grasses; in southern Wyoming,
77 percent forbs and 12 percent grasses; and in northern Wyoming, 93 percent
forbs and 7 percent grasses.
Direct observations of the grasshoppers feeding in their natural habitat
west of Laramie, Wyoming totaled 13 bouts on Arenaria congesta,
13 on Poa spp., and 9 on Taraxacum laevigatum. Average times
spent feeding on these plants were A. congesta, 3 minutes; Poa
spp., 1.8 minutes; and T. laevigatum 1.8 minutes. These results
suggest that A. congesta was the preferred food plant. In a northern
Colorado mountain meadow, A. fendleri served as the chief food plant.
Crops of the alpine grasshopper contained 35 percent of this plant on both
10 and 23 August 1967 (Table
The number of food items per crop is of importance to the nutrition
of grasshoppers; laboratory tests have shown increased weight, survival,
and egg production of individuals among several species of Melanoplus
when fed more than one kind of food plant. Adults of the alpine grasshopper
usually contain more than one species of host plant in their crops. Collected
from a meadow of the Laramie range, males contained an average of 1.2 items
and females 3.2 items. Collected from a meadow of the Big Horn Mountains,
males contained an average of 1.8 items and females 2.4 items. These differences
between the sexes were statistically significant.
Dispersal and Migration
Possessing long wings and developed wing muscles, the alpine grasshopper
is able to fly evasively and to disperse. Within the center of its distribution
in the Big Horn Mountains of northern Wyoming, the species inhabits a high
percentage of the available montane meadows, which suggests effective dispersal.
Additional evidence for dispersal was the collection of one adult male
on 5 September 1995 in a bunchgrass-sagebrush habitat lying at an altitude
of 7,300 feet - a foothill locale atypical for the species. None of the
species was collected in this site on 3 August 1995 nor in the previous
year on 25 July 1994. On the other hand, no adults have been found in grasshopper
glaciers with other species that inhabit montane meadows, a fact suggesting
that the alpine grasshopper disperses primarily by short, low flights.
When flushed, the adult alpine grasshopper appears more often to jump
than to fly. Nymphs (instar V) and adults jump from 4 inches to 3 feet
at air temperatures of 46° to 70°F. Adults fly short distances
at temperatures of 54° to 70°F. The flight is low and silent.
The alpine grasshopper is a medium-sized, long-winged species (Fig.
6 and 7). Head, thorax, and tegmen are usually gray but may range in
color to shades of light tan. The venter and sides of the abdomen are cream
colored. The dark dorsal stripe of the hind femur is continuous and may
fill most of the medial area, often the stripe has a wedge-shaped mark
dorsally in the middle; the lower medial area is pale gray or tan (Fig.
8). The upper marginal area is tan and marked by three black transverse
bars. The hind tibia is green, blue, or pink. The male cercus is bifurcate,
the dorsal arm is stubby and blunt, and the ventral arm is sharply pointed
and both arms bend medially (Fig. 9).
The smaller Melanoplus infantilis, which often resides alongside
the alpine grasshopper in mountain meadows, has a similar bifurcate cercus,
but the lower arm ends in a rounded blunt tip and does not bend toward
the median (compare the two).
The nymphs are identifiable by their color patterns, shape, and structures
(Fig. 1-5). The early nymphs and some of the
late nymphs are recognizable in the field by their green bodies, dark compound
eyes, and prominent dark dorsal stripe of the hind femur.
1. Head with face nearly vertical and colored plain green, often tan
in older instars; ridges of frontal costa and preocular ridges spotted
brown; a black bar is present on the side of the head behind the compound
2. Pronotal disk with dusky band, which is spotted brown and present
on each side; the band continues onto the meso-and metanotum or the wing
pads of older instars and to the end of the abdomen. The venter of the
thorax and abdomen is green or pale tan, sometimes with pale brown spots.
3. The hind femur is green or tan and has a prominent dark dorsal stripe,
often with a light dorsal wedge in the middle. The lower medial area and
the lower marginal area are pale green or pale tan. The upper marginal
area is green or tan.
4. Nymphs may change body color when they undergo metamorphosis. All
specimens are green in instar I. In Instar II approximately 85 percent
are green and 15 percent are cream or pale tan; in instars III and IV approximately
52 percent are green and 48 percent are cream or pale tan; in instar V
approximately 20 percent are green and 80 percent are tan.
Before eggs of the alpine grasshopper will hatch, they require a long developmental
period in the soil. A study of eggs laid in the Big Horn Mountains of Montana
and Wyoming revealed that the majority of eggs (92 percent) required three
years of development before hatching and a smaller number (8 percent),
two years. None hatched in one year; the eggs laid in one summer were unable
to hatch the following spring. The cause for the delay is unknown but may
be due to both cold temperatures of mountain soils and to an extended diapause
of the embryos.
In mountain meadows of Wyoming, eggs of the alpine grasshopper start
hatching from early to late June. The precise time depends on seasonal
temperatures that affect snow melt and the thawing and warming of the soil.
The period of hatching is short, ranging from 6 to 17 days.
In spite of cold night temperatures and frequent cold rains in the mountain
environment, nymphs of the alpine grasshopper develop rapidly to the adult
stage. During the day in their meadow habitats, they bask in the warming
rays of the sun and then at night they seek shelter in ground litter and
crowns of grass insulating themselves from night air temperatures that
range from 34° to 53°F. Nymphal periods have been found to last
from 25 to 40 days. The shortest period of 25 days occurred in 1955 in
a meadow lying at 9,800 feet in the Snowy Range west of Laramie, Wyoming.
Daily scouting of the meadow revealed the first hatch of nymphs on June
21 and the first adult on July 16. In 1994 and 1995, slightly longer nymphal
periods of 35 and 38 days were found to occur in a Pole Mountain meadow
east of Laramie (altitude 8,600 feet). In 1994, in a Big Horn Mountain
meadow of northern Wyoming (altitude 8,200 feet), the nymphal period took
37 days. Both male and female alpine grasshoppers have five instars.
Adults and Reproduction
The alpine grasshopper reaches the adult stage by early July in the mountains
of Wyoming . In 1994, adults were first discovered on July 8 in both northern
and southern mountains. In the Snowy Range study meadow west of Laramie,
Wyoming (altitude 9,800 feet), adults were first observed on 16 July 1955.
The first observation of mating in this site was noted on August 12, and
the first oviposition a week later. Females select bare ground between
clumps of grass to deposit groups of 8 to 12 eggs. Although populations
of adults dwindle through the summer, residual individuals are still present
in mid September. These individuals continue to mate and presumably to
deposit eggs. Because alpine grasshoppers retreat into shelters when weather
becomes inclement, early frosts do not affect their survival.
The pods are 1 to 1 1/8 inches long and curved at the bottom so that
the terminal section with eggs, 3/8 inch long, lies diagonally in the soil.
Offwhite froth fills the top section of the pod; tan froth surrounds the
eggs at the bottom. Eggs are yellow or pale tan and 4.3 to 5.0 mm long
The alpine grasshopper enjoys a high frequency of occurrence in mountain
meadows of Wyoming. In the Big Horn mountains of northern Wyoming, 12 of
14 meadow sites (85 percent) surveyed in 1994 were inhabited by resident
populations. Densities were low in all populations, ranging from less than
0.1 to 0.5 adult per square yard. The highest density of adults ever recorded
in the Wyoming annual grasshopper survey (1988-94) was 3.7 adults per square
yard in a meadow of the Big Horn Mountains (13 August 1991). The entire
grasshopper assemblage living in this site numbered 16 adults per square
yard. Densities of the six species were: Bruneria brunnea, 5.7;
M. alpinus, 3.7; M. bruneri, 2.4; M. borealis, 2;
Camnula pellucida, 2; and Chorthippus curtipennis, 0.2. The
study of the alpine grasshopper in the Snowy Range in 1954-55 revealed
densities ranging from 0.4 to 0.9 adult per square yard. To date, no irruptions
of the alpine grasshopper have been observed even in years favorable for
outbreaks of M. borealis and M. bruneri. The requirement
of alpine grasshopper eggs to be in the soil for two to three years before
hatching complicates the study of population ecology of this species.
The alpine grasshopper is a geophilous species resting, walking, feeding,
and performing other activities on the ground. At night, the grasshoppers
rest deep in grass crowns or wedge themselves as much as 2 inches below
the soil surface alongside a rock or boulder. Two hours after sunrise they
emerge from their shelters and begin to bask, resting horizontally on bare
ground or on litter. They turn a side perpendicular to the rays of the
sun and lower the associated hindleg, exposing the abdomen. In meadows
of the Big Horn Mountains of northern Wyoming, basking begins about 7:30
a.m. DST and may last for two to three hours. Feeding occurs in the forenoon
and again in the afternoon. During a feeding observation in a Big Horn
Mountain meadow at 9:51 a.m. DST, an adult male sitting horizontally on
the ground was seen to feed on a short green sprout from its tip to base.
Adults may remain inactive on the ground in sheltered spots for long periods
of time during the day and may not move unless disturbed by roving insects,
wind, or rain. A second period of basking occurs in late afternoon. Then
as evening approaches and temperatures fall, the grasshoppers enter their
Alexander, G. and J. R. Hilliard, Jr. 1969. Altitudinal and seasonal distribution
of Orthoptera in the Rocky Mountains of northern Colorado. Ecol. Monogr.
Bergstrom, R.C. 1955. Life history of the grasshopper Melanoplus
alpinus Scudder. M.S. thesis, University Wyoming, Laramie, WY.
Brusven, M.A. 1972. Differentiation and ecology of common Catantopinae
and Cyrtacanthacridinae nymphs (Orthoptera: Acrididae) of Idaho and adjacent
areas. Melanderia 9: 1-31.
Hansen, R.M. and D.N. Ueckert. 1970. Dietary similarity of some primary
consumers. Ecology 51: 640-648.
Kreasky, J.B. 1960. Extended diapause in eggs of high-altitude species
of grasshoppers, and a note on food-plant preference of Melanoplus bruneri.
Ann. Entomol. Soc. Am. 53: 436-438.
Rentz, D.C. 1962. Melanoplus alpinus Scudder in California. Pan-Pacific
Entomol. 38: 167-168.
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