Melanoplus kennicotti Scudder
Link directly to photos of adults, nymphs,
Distribution and Habitat
M. kennicotti continental distribution map
Wyoming distribution map
The Kennicott grasshopper, Melanoplus kennicotti, ranges in a
wide band along the Rocky Mountains from Alaska to New Mexico. It inhabits
the grasslands of mountain meadows and parklands and the western edge of
the northern mixedgrass prairie. The species resides at elevations ranging
from 100 feet in Alaska to 11,060 feet in the Absaroka Range in Wyoming.
In Alaska the species inhabits open areas of the mixedgrass-forb-moss association
at elevations of 100 to 450 feet.
A feeder on forbs and grasses, the Kennicott grasshopper is a potential
pest of forage in mountain parklands. It is a small species that during
years of outbreaks, makes up for its size by large numbers. Adding its
impact to the damage caused by other pest species during outbreaks, it
contributes to the depletion of livestock and wildlife forage in parklands.
Occasionally, it is the predominant species of the grasshopper assemblage,
but no quantitative studies of its damage have been made. Live males weigh
an average of 173 mg and live females 285 mg (dry weight males 60 mg, females
The Kennicott grasshopper feeds on a variety of forbs and grasses. Observations
of released adults in their natural habitat in early fall revealed that
they fed upon several forbs: dandelion, a sagebrush (Artemisia tripartita),
prairie chickweed (Cerastium arvense), and an unidentified forb
sprout approximately 1 inch tall. The latter plant was consumed to ground
level in 6 minutes. One adult was observed to feed on prairie junegrass
which had greened up after late summer rains. It ate the distal 1 inch
of a 2-inch-tall leaf. Field observations were limited both by time spent
watching individual grasshoppers and by the short window of adult life
scrutinized in fall. Observations should be made ideally from late spring
to early fall so that grasshoppers may encounter all kinds and stages of
plants in the habitat. This mountain study site had a rich floral diversity
including a minimum of 20 forbs, 9 grasses, and 2 sedges.
Confined in cubic-foot cages on transplanted sod from the study site
west of Tie City, Wyoming, adults were observed to feed on dandelion, prairie
chickweed, prairie junegrass, wild buckwheat (Eriogonum umbellatum),
fendleri, and Poa cusickii.
Laboratory two-choice tests showed that dandelion, alfalfa, Cryptantha
thyrsiflora, and downy brome were preferred; Erigeron eatoni,
villosi, Kochia scoparia, and Poa pratensis were rejected.
Adults consumed some of Astragalus sp. but results were unclear.
Although these observations and others of feeding by the Kennicott grasshopper
show that it is a polyphagous species consuming both forbs and grasses,
they do not provide vital information about its diet. Such observations
fail to reveal the proportions of food items ingested and the changes in
diet that are sure to occur seasonally. Only a detailed study by quantitative
analysis of gut contents of grasshoppers taken from several habitats at
different densities and times of the season will disclose fully the Kennicott
grasshopper's food habits.
Dispersal and Migration
Flushed flight of the Kennicott grasshopper is short (4 to 5 feet) and
low (6 to 8 inches above the ground surface). The flight is silent and
usually straight but may be circuitous. Direct evidence for voluntary flight
is lacking. No migrating swarms have been seen and reported and no frozen
specimens have been found on glaciers. Likewise no appetitive flying has
been observed in study sites of the Laramie Range. Nevertheless, a study
of population densities in the infested square mile area west of Tie City,
Wyoming, provide circumstantial evidence for a slow dispersal from the
center where densities were highest to the edges where densities were lowest.
Less likely is the possibility that of apparently uniform parkland the
central area was a more favorable habitat than all four perimeter sites.
The Kennicott grasshopper is a small, dark gray member of the species-rich
genus, Melanoplus. The body patterns are dark gray with contrasting
pale gray and tannish gray areas (Fig. 6 and 7).
The wings are long reaching approximately the end of the abdomen and the
apices of the hind femur (male wings terminate from 1 mm before to 1.5
mm beyond the hind-femur apex, female wings end 0.5 to 1.5 mm before the
apex). The hind femur is yellow ventrally and the medial area is marked
by three dark gray bands; the middle one has a feather-and-shaft appearance;
occasionally the pattern is indistinct when the medial area is entirely
dark. The tibia are olive, buff, or blue. The distinctive male cerci are
rectangular and stubby (Fig. 8).
The furcula is short with acutely pointed processes. The end of the subgenital
plate bears a nipple. The venter of the abdomen is cream or pale gray and
The nymphs are identifiable by their color and color patterns (Fig.
1. Head tan or pale gray, each ridge of frontal costa with a row
of 8-12 fuscous spots; antennal segments black with anterior annulus cream-colored;
compound eye brown with tan spots, a transverse dark bar crosses center
of eye, each side of dark bar with adjacent tan bar; top third of eye pale
brown, bottom third dark brown.
2. Crescent on side of head and pronotal lobe cream-colored or
tan, crooked on lobe (Fig. 1-4 and 9),
may be interrupted on lobe (Fig. 5), or
3. Hindleg: medial area of femur with light and dark transverse
bars and areas, middle dark bar shaped like feather and shaft of arrow
(See Fig. 3 for clear depiction); marginal
area with 2 tan and 2 black transverse bars in instar I, 3 tan and 4 black
transverse bars in instars II to V; hind tibia with side black or gray
in instar I, gray or tan in instars II to V, front of tibia and spines
black in all instars.
4. Venter of thorax and abdomen pale gray or tan, spotted brown.
5. General color gray, tan, or cream with many fuscous spots,
a few specimens melanistic.
Two characters useful in identifying the nymphs of the Kennicott grasshopper
are the crooked crescent and the feather-and-shaft marking on the medial
area of the hind femur.
From eggs that overwinter in the soil, the Kennicott grasshopper hatches
in late spring. It is one of the early hatching species in the montane
environment along with Melanoplus alpinus, Bruneria brunnea,
pellucida, and several others. These early species hatch about one
month after snow melt exposes parkland vegetation. In the mountain study
site west of Tie City, Wyoming (Laramie Range T15N, R72W, Sec 15 NW, elevation
8,600 feet), the Kennicott grasshopper along with M. alpinus and
brunnea began to hatch 6 June 1994 and 24 June 1995. In the same site,
the hatching of M. infantilis and M. sanguinipes did not
begin until 5 July 1994 and 5 August 1995. This would place these two species
in the intermediate hatching group of montane species. However, at lower
elevations as in the grasslands of the High Plains, they belong to the
early hatching group. The length of time that the hatching eggs of the
Kennicott grasshopper have lain in the soil is unknown. The eggs may have
been laid the previous summer or two or more summers earlier.
The nymphs develop early in summer when montane weather is variable but
vegetation is green and nutritious. A few days of cold rain or snow may
occur but most days are sunny and warm. The length of the nymphal development,
as measured from first hatch to first adult, is short. In the parkland
west of Tie City, Wyoming, this period was calculated to be 29 days in
1994 and 38 days in 1995. The length of the latter figure may be an over
estimate due to difficulties in netting the first adults.
Adults and Reproduction
In mountain habitats the adult stage of the Kennicott grasshopper is reached
in early summer. In the parkland west of Tie City, Wyoming, adults appeared
2 July 1994 and 29 July 1995. For comparison, adults of M. infantilis
appeared 7 August 1994 and 29 August 1995. Survival of adults of the Kennicott
grasshopper was high through August and the first half of September, but
declined noticeably by late September. A small number of hardy adults survived
into October. Sampling of the population in 1995 showed that in 200 semicircular
sweeps of a 15-inch diameter insect net, an average of 3 adults were captured
in August but by 18 September only one adult was captured.
Females caged with males oviposited into containers of bare soil. Pods
were curved and 3/4 to 1 inch long. Three pods contained 12 eggs each.
Eggs were pale tan and 4.2 to 4.6 mm long (Fig.
The Kennicott grasshopper maintains a low frequency of occupation of mountain
meadows and parklands in Wyoming, as indicated by results of the Wyoming
Grasshopper Survey. From 1991 to 1994, 256 sites in the Rocky Mountains
were investigated. In only 35 sites was the Kennicott grasshopper collected
(14 percent frequency). For comparison, the alpine grasshopper, M. alpinus,
occupied 83 of the 256 sites (32 percent frequency) and the Bruner slantfaced
grasshopper, B. brunnea, occupied 95 sites (37 percent frequency).
The low frequency of the Kennicott grasshopper is probably a biased account
of its presence due to this species' behavior on being disturbed. When
flushed, individuals either fly low a short distance or hunker down and
become quiescent. Thus, at low densities it may be under sampled by scouts
using insect sweep nets. A more reliable method of documenting the presence
of the Kennicott grasshopper is to visually search and capture grasshoppers
by hand. This method was begun in 2001 in the parkland west of Tie City,
Wyoming. In this area in mid September, sampling with an insect net yielded
no Kennicott grasshopper specimens in the first 100 sweeps and one female
in the second 100 sweeps. However, in two 10-minute search-and-capture
samples, four specimens were caught in the first search and three in the
Like most pest species of grasshoppers, populations of the Kennicott
grasshopper may range numerically between years and among locations. The
Wyoming Grasshopper Survey has recorded densities ranging from 0.02 to
12 adults per square yard. The latter density of the Kennicott grasshopper
was discovered in 1995 in parkland on the western slope of the Big Horn
Mountains (Big Horn County, Wyoming T51N R88W Sec 33 SE). The density of
the assemblage of three species was estimated at 36 adults per square yard,
brunnea was dominant at 18 adults per square yard, the Kennicott grasshopper
was next at 12 adults, and Melanoplus bruneri was last at 6 adults.
In 1995 another heavily infested site was discovered. This time in parkland
of the eastern slope of the Big Horn Mountains (Washakie County, Wyoming
T42N R86W Sec 23 NW) in which the Kennicott grasshopper was the dominant
species at 5 adults per square yard in an assemblage of 5 species numbering
15 adults per square yard. No long-term study of these or any sites has
been made to determine how many years are needed for the Kennicott grasshopper
to reach outbreak densities nor how long outbreaks last.
Important characteristics of local grasshopper populations are the sizes
of inhabited areas and the density of individuals. An opportunity to determine
these parameters for the Kennicott grasshopper arose in the summer of 2001
in the infested parkland west of Tie City, Wyoming. The area of habitation
measured approximately 1 square mile (0.5 x 2 miles). The absolute density
was less than 0.1 adult per square yard throughout the inhabited area.
Because of the low numbers, relative densities were taken at 12 stops,
0.2 to 0.3 miles apart, along gravel and dirt roads by the 10-minute search-and-capture
method. Results showed that the relative densities were highest near the
center with 4 to 5 adults and lowest at the edges with 1 adult per 10-minute-search-and-capture.
The evidence suggests gradual dispersal from the center and slow expansion
of the inhabited area.
Observations reveal that the Kennicott grasshopper is a highly geophilous
species. It rests, basks, feeds, and shelters on the ground. Due to low
densities in the study site, field observations were made of adults caught
and released in their natural habitat. During basking the adults sit on
bare ground or litter, turn a side perpendicular to rays of the sun, and
lower the associated hindleg to expose the abdomen (flanking). Air and
soil surface temperatures in mountain parklands fall very low during the
night at times reaching 35°F. Because cold body temperatures result
in cold stupor of grasshoppers, movement from shelters to basking places
may not begin until 1 hour after sunrise. Basking lasts from 2 to 3 hours.
To determine how the Kennicott grasshopper responds to high temperature,
adults were released in native grassland in an outskirt of Laramie, Wyoming
(elevation 7,165 feet). At 11:35 a.m. DST when the soil surface temperature
reached 120°F and air 85°F, a female crawled from bare ground to
the partial shade of blue grama and reared up diagonally to face the sun
directly, thereby minimizing radiant heating. There she remained quiescently,
even refusing to flush.
Basking begins again in the afternoon when ground surface temperatures
have fallen to 72°F and air temperatures to 60°F. Basking continues
until nearly sunset. Close to sunset adults crawl several inches to choose
a shelter on the ground that is surrounded by vegetation. They sit horizontally
on bare ground or litter and remain quiescent, presumably through the night
as it becomes darker and colder.
Larsen, J.C., J.A. Hutchason, and T. McNary. 1988-2001. The Wyoming Grasshopper
Information System. Cooperative Agricultural Pest Survey, University of
Vickery, V.R. 1997. Orthopteroid insects (Orthoptera) of the Yukon.
Insects of the Yukon: biological survey of Canada (Terrestrial Arthropods),
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