Melanoplus keeleri (Thomas)
Link directly to photos of adults, nymphs,
Distribution and Habitat
M. keeleri continental distribution map
Wyoming distribution map
The Keeler grasshopper ranges widely in North America inhabiting upland
grasslands from the Atlantic coast to the Great Basin and from southern
Canada to southern United States. In the west it is a common inhabitant
of the tallgrass prairie and the taller types of the mixedgrass prairie.
The Keeler grasshopper is a minor pest of rangeland forage. When present,
populations occur at low densities in the mixedgrass, tallgrass, and sand
prairies. Furthermore, the nymphs and adults do not consume native grasses
in significant amounts, preferring to eat forbs of low forage value. Because
several forages in the bean family are among its preferred food plants,
the Keeler grasshopper may become a pest in pastures seeded to mixtures
that include legumes. In such situations it is usually subdominant to major
pest species such as the migratory, redlegged, and twostriped grasshoppers.
The Keeler grasshopper merely adds a small amount to the more serious damage
of the others. Likewise, this grasshopper does not appear to be a serious
pest of cultivated crops. It has been discovered in small numbers in North
Dakota alfalfa fields ranking eighth in abundance after seven other melanoplines.
It did feed on the alfalfa, however, as 19 out of 26 crops examined contained
fragments of this legume.
The Keeler grasshopper is a medium-sized species. Live weights of males
average 252 mg and of females 343 mg (dry weights: 73 mg and 100 mg, respectively).
The Keeler grasshopper feeds on a wide variety of forbs. Field observations
and examinations of crop contents reveal that a minimum of 52 species are
consumed in variable amounts. These belong to 17 plant families. Additionally,
records show that a small amount of feeding occurs on seven species of
grasses and one sedge. The Keeler grasshopper has also been observed to
feed on cabbage and the leaves of apple and plum. Only two plant families
embrace the primary host plants: the sunflower family (Asteraceae) and
the bean family (Fabaceae).
The kinds of plants present in the habitat influence greatly the diet
of this grasshopper. In the tallgrass prairie of eastern Kansas, three
species serve as the chief host plants: western ragweed, cudweed sagewort,
and Missouri goldenrod; four species in the mixedgrass prairie of central
Nebraska: breadroot scurfpea, aromatic aster, common sunflower, and prickly
lettuce; four species in the sand prairie of southeast North Dakota: green
sagewort (Artemisia glauca), western ragweed, leadplant, and cudweed
sagewort; and four species in the mixedgrass prairie of northcentral Colorado:
flexuosus, cudweed sagewort, scarlet globemallow, and undetermined
species of the sunflower family. Different host plants and dietary combinations
no doubt occur in other sites. Of economic interest is the fact that several
introduced forages belonging to the bean family - alfalfa, lespedeza, sweetclover,
and probably others - are among this grasshopper's preferred food plants.
Although primarily a forb feeder, the Keeler grasshopper ingests small
or trace amounts of grass. Examination of crop contents reveals fragments
of western wheatgrass, blue grama, needleandthread, downy brome, Japanese
brome, smooth brome, and Kentucky bluegrass. Cage tests show that among
six species of grasses occurring in eastern Kansas, tall fescue was preferred,
followed closely by smooth brome. Fragments of Penn sedge have been found
in crops of Keeler grasshoppers collected in southeast North Dakota.
One observation was made of this grasshopper feeding on the host plant,
glaber. A female sitting diagonally head-up on the dry culm of Japanese
brome that leaned on the host plant fed on the stub of a leaf that had
been previously fed upon across its entire width. Observations of P.
glaber plants revealed more injury to top leaves than the low, rosette
leaves lying near ground level. Lateral edges of top leaves, which are
about 3 inches long, exhibited uneven gouges 3/8 to 5/8 inch long and 1/8
inch deep. Some leaves had been attacked from the tips and only basal stubs
remained. This limited evidence suggests that this grasshopper feeds close
to where it perches on the plant. In the case of Penstemon glaber,
the grasshopper fed primarily on leaves 4 to 10 inches high.
Dispersal and Migration
Western specimens of the Keeler grasshopper possess long wings that range
from nearly reaching the end of the abdomen to 4 mm beyond. Despite having
the structures necessary for flight, they do not appear to disperse much
but remain most often in the relatively thick vegetation of midgrasses
and forbs within their habitat. However, some evidence for dispersal exists.
Two adult accidentals were collected in a montane site northwest of Boulder,
Colorado at an altitude of 7,600 feet. In this area the species is resident
up to 6,700 feet. Other evidence for dispersal comes from the collection
of two fifth-instar nymphs in a mixedgrass study site (Platte County, Wyoming)
on 25 July 1992 where previously the species had not been seen or collected
for a period of 13 years (1968-81). Evidently, adults dispersed into the
site between 1982 and 1991. Further evidence for dispersal comes from the
George Reserve in Michigan, where accidentals (erratics) have been taken
in nonresident habitats such as shady oak-hickory woodland and semipermanent
Adults that are flushed jump or more often fly short distances of 2
to 4 feet at heights of 8 to 12 inches. The flight is straight and silent
and the landing is on vegetation or bare ground. On vegetation they land
vertically head-up and on bare ground they land horizontally facing away
from the intruder.
In the west, the Keeler grasshopper is a colorful long-winged, medium-sized
grasshopper (Fig. 6 and 7), in contrast to many
eastern specimens that are dark brown and dull. Males are recognizable
by the distinctive shape of the cercus, which is bifurcate with the dorsal
arm larger than the ventral (Fig. 9).
Both sexes possess a distinctively shaped femoral stripe. Located on the
outer face of the hind femur, the stripe is solid fuscous (not cut by any
light band) and narrows toward the base (Fig.
8). The hind tibiae are red and the body is brown and yellow.
The nymphs are identifiable by their structures, color patterns, and
shape (Fig. 1-5).
1. Head with face nearly vertical and colored fuscous except frequently
yellow around base of antenna; compound eye brown or fuscous and marked
distinctively by two parallel transverse yellow stripes (See Figure
2 for clear picture); sides of head yellow, top of head yellow in instars
I and II, reduced to median yellow band or all black in older instars.
2. Pronotum with disk fuscous, divided by yellow median band, lobes
yellow and marked by an anterior diagonal dark stripe in instars I and
II, faint or lacking in instar III, solid cream or yellow in instars IV
3. Hind femur yellow with solid black femoral stripe; hind tibia gray.
4. General body color yellow and black. Venter often canary yellow.
The Keeler grasshopper is a late-hatching species. Depending on the year,
it begins to hatch from early to late June in the mixedgrass prairie of
Colorado, hatching about three weeks after the migratory grasshopper, Melanoplus
sanguinipes, which often shares the same habitat. In Larimer County,
Colorado, first instars were collected on June 4 in 1992 and on June 22
in 1993. Limited data indicate that the hatching period is short - from
one to two weeks.
In their natural habitat within the mixedgrass prairie, Keeler grasshoppers
develop through five instars in approximately 46 days. In Larimer County,
Colorado, the first adults were observed July 31 in 1993 and July 27 in
1994. On these dates the majority of the population consisted mainly of
instars IV and V.
Adults and Reproduction
Adults begin to emerge during the latter part of July and continue emerging
for approximately three weeks in the mixedgrass prairie of northcentral
Colorado. By mid August, 85 percent of the population is fledged. At lower
altitudes emergence of adults occurs earlier. In eastern North Dakota,
adults are present during the first week of July; in Iowa, adults have
been found as early as June 23. Although maturation of adults has not been
studied, a few facts are known. Courtship in this species is brief. Without
preparatory signals, the male jumps on a female. A nonresponsive female
shakes her hindlegs and kicks away the unwanted suitor, but a responsive
female scarcely struggles while the male produces bursts of femur shaking
and attaches his genitalia. The duration of copulation is unknown. Two
observations of pairs in copulo were made in the mixedgrass prairie of
Colorado, one on 9 August 1994 at 11:45 a.m. DST and another three days
later at 10:31 a.m. Adults peak numerically in mid August. They then gradually
dwindle, but a fair number are still present and active in October. In
southeast North Dakota the females have been observed to oviposit in small,
bare or sparsely vegetated areas. The egg pods are 3/4 to 1 inch long,
curved, and contain 20 to 22 light tan eggs 4.0 to 4.3 mm long (Fig.
The center of distribution of the Keeler grasshopper appears to be in the
midwest where it is common in upland grass-herb habitats and at times becomes
the dominant species in the grasshopper assemblage. In the western peripheral
zone of its geographic range, it is rare in the normal mixedgrass and shortgrass
prairies. In this zone it occupies edaphic habitats characterized by relatively
tall grasses and herbs that occur on well-watered slopes and along roadsides.
An edaphic site in the mixedgrass prairie of northcentral Colorado affords
a favorable habitat in which populations of the Keeler grasshopper have
persisted for at least eight years: 1987 to 1994. In 1994 it was the dominant
species in an assemblage of nine species with a total density of eight
grasshoppers per square yard. On 11 August 1994, the Keeler population
measured four individuals per square yard. At this time 75 percent were
adult and 25 percent were late instars. By 29 September 1994, the population
decreased to 0.2 adults per square yard, indicating a 6 percent daily mortality
over the adult period.
A study site in the sand prairie of southeastern North Dakota (Sheyenne
National Grasslands) harbored populations of the Keeler grasshopper for
at least ten years, 1959 to 1968. Measurements of relative abundance indicated
a subdominant position throughout this period. In 1960, however, it ranked
second after Eritettix simplex and then decreased in density through 1962
and fluctuated in abundance to 1968.
Inhabiting sites of thick, tall and mid grasses and tall forbs, the Keeler
grasshopper spends most of its time perched on vegetation. At night, individuals
usually rest vertically, head-up on stems of forbs at heights of 8 to 14
inches above the ground. An occasional individual may rest diagonally or
horizontally on the stem of a fallen, dead forb or on the cladode of a
prickly pear cactus. In the morning when rays of the sun strike them, they
begin to bask. In the study site on August 9 to 12, 1994, a hill to the
east hid the rising sun until 7:33 a.m. DST. Basking grasshoppers were
noticed an hour later. Still on the vegetation, they turned a side perpendicular
to the sun and lowered the hindleg to expose the abdomen. They basked for
two hours or longer and some fed during this time on leaves of the host
plant. One observation was made of a female feeding on ground litter at
11:05 a.m. Shortly before sunset, the grasshoppers settled on their host
plants and presumably stayed at rest until morning. Temperatures declined
from 80°F at sunset to 60°F at sunrise, at which time the grasshoppers
were quietly roosting.
Cantrall, I.J. 1943. The ecology of the Orthoptera and Dermaptera of the
George Reserve, Michigan. Misc. Publ. Mus. Zool. Univ. Michigan, No. 54.
Gangwere, S.K., F.C. Evans, and M.L. Nelson. 1976. The food habits and
biology of Acrididae in an old-field community in southeastern Michigan.
Great Lakes Entomologist 9: 83-123.
Lambley, J.O., J.B. Campbell, and H. Knutson. 1972. Food preferences
of grasshoppers in six planted pastures in eastern Kansas. J. Kansas Entomol.
Soc. 45: 59-92.
Mulkern, G.B. 1980. Population fluctuations and competitive relationships
of grasshopper species (Orthoptera: Acrididae). Trans. Amer. Entomol. Soc.
Mulkern, G.B., K.P. Pruess, H. Knutson, A.F. Hagen, J.B. Campbell, and
J.D. Lambley. 1969. Food habits and preferences of grassland grasshoppers
of the North Central Great Plains. North Dakota Agr. Exp. Stn. Bull. 481.
Otte, D. 1970. A comparative study of communicative behavior in grasshoppers.
Misc. Publ. Mus. Zool. Univ. Michigan, No. 141.
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