Arphia conspersa Scudder
Link directly to photos of adults, nymphs,
Distribution and Habitat
A. conspersa continental distribution map
Wyoming distribution map
The specklewinged grasshopper enjoys a wide distribution in western
North America that stretches from Alaska to Mexico. It inhabits all of
the grassland prairies and penetrates desert shrub communities wherever
grasses make up part of the vegetation. In Colorado and Idaho, resident
populations have been found in mountain meadows and other open grasslands
up to 11,000 feet.
Although the specklewinged grasshopper feeds on quality forage, its impact
on grazing land is minimal due to low densities throughout its distribution.
Populations in desert grassland and in shortgrass and mixedgrass prairie
have been determined to range from 0.05 to 0.1 adults per square yard.
In mountain habitats, numbers are less, ranging from approximately 40 to
120 adults per acre. In some apparently suitable habitats they appear to
be absent. This species is in the largest category of the three size divisions
of rangeland grasshoppers. Live weight of males from mixedgrass prairie
in Platte County, Wyoming averaged 251 mg, and of females 776 mg (dry weight:
males 86 mg, females 178 mg). Individuals from mountain habitats are smaller;
live weights of individuals from 10,170 feet in central Colorado averaged
194 mg for males and 494 mg for females.
The specklewinged grasshopper feeds primarily on grasses and sedges. Sixteen
species of grasses and three species of sedges have been recorded in crop
contents. Specific host plants ingested depend on both the grasshopper's
preferences and the availability of plants in diverse grassland habitats.
In the sand prairie of southeastern North Dakota, Kentucky bluegrass made
up 50 percent of the diet; in the mixedgrass prairie of central Nebraska,
prairie junegrass made up 67 percent; in the mixedgrass prairie of eastern
Colorado, western wheatgrass and needleandthread in equal quantities made
up 58 percent of the diet; and in the shortgrass prairie of northern Colorado,
blue grama (27.6 percent), western wheatgrass (18.8 percent), and downy
brome (17.6 percent) made up 64 percent of the diet. Other plants found
in substantial amounts include threadleaf sedge, needleleaf sedge, sand
dropseed, and sixweeks fescue. Small amounts of forbs (12 species), fungi,
and arthropods are ingested by this grasshopper. No doubt, the number of
grasses and sedges known to be ingested is still far short of the actual
number fed upon by this grasshopper.
The specklewinged grasshopper feeds mainly from a horizontal position
on the ground, and eats dry grass litter, recumbent attached leaves, or
green leaves cut by itself. It attacks a standing leaf by raising up diagonally
on its hind legs and cutting the leaf about one-half to one inch above
the base. It may hold onto the cut portion with the front tarsi and feed
to the tip, or it may drop the cut portion and return to the ground to
eat the fallen leaf. Sometimes it will eat the remaining green stub from
a horizontal position.
Dispersal and Migration
The specklewinged grasshopper has strong powers of flight, possessing long
wings that extend beyond the end of the abdomen in both males and females.
Appetitive flights of the males occur regularly and are accompanied by
a crackling sound called crepitation. These flights are comparatively rare
in females. The sound is produced by the wings, but an explanation of the
exact mechanism remains in dispute. Appetitive flights last one to three
seconds and describe an arc 6 to 10 feet long and 3 feet high. The flights
are a part of courtship and function to bring the sexes together. Because
of its behavior to aggregate, the specklewinged grasshopper has low vagility.
Evidence for its dispersal is present in montane settings. It often colonizes
regrown road cuts and cleared chaparral within five years, wherever nearby
populations are present. No records of migration exist for this species.
Evasive flights are made by both males and females beginning about three
hours after sunrise when soil temperatures have risen above 60°F. The
flights range from 4 to 45 feet in length and from 6 inches to 2 feet high.
They are usually sinuous and accompanied by crepitation. Silent escape
flights may occur and extend from 30 feet to over several hundred feet
with the wind. The fleeing grasshopper lands horizontally on the ground
and often turns to face the intruder.
The specklewinged grasshopper, prevalent as adults in spring, is a wide-ranging
western species. Its genus, Arphia, consists of 16 species. Of these,
only the redwinged grasshopper, Arphia pseudonietana (Thomas), has
an equally wide distribution in the West. Adults of this species, present
in late summer and fall, are separated seasonally from adults of the specklewinged.
The adult specklewinged grasshopper (Fig. 6 and
7) is a large rangeland species, the female being much larger than
the male. The lateral foveolae of the head are triangular or quadrilateral.
The median carina of the pronotum is low but distinct, uniformly elevated,
and incised once in front of the middle (Fig.
8). The body is brown except for a yellow abdomen. The tegmina are
brown with dark brown speckles and, when folded, often form a pale tan
or yellow median stripe. The disk of the hind wing is usually red but may
be yellow (Fig. 9). The hind tibia
is pale yellowish green with a fuscous annulus at each end.
The nymphs (Fig. 1-5) are identifiable by
their shape, external structure, and color patterns.
1. Instar I. Head conspicuously large and rounded; segments of maxillary
and labial palps brown with distal ends pale yellow. General body color
dark brown. Pronotum with low, entire median carina; lateral lobe black
with a triangular light tan patch postero-ventrally (Fig.
1). Hind tibia dark red; hind tarsus black on first segment and distal
two-thirds of last segment with middle white.
2. Instars II and III. Head rounded, face nearly vertical, lateral foveolae
triangular or quadrilateral. Pronotum with low, median carina (entire or
weakly incised) and with disk tectate (rooflike); lateral lobes of pronotum
brown with dark brown speckles and marks (without triangular light patch).
Hind tibia shiny black; hind tarsus black at both ends and pale in middle.
3. Instars IV and V. Head vertically elongated, not as rounded as in
earlier instars; lateral foveolae triangular or quadrilateral; segments
of maxillary and labial palps mainly pale. Pronotum with low, uniformly
elevated median carina incised once in front of middle; disk of pronotum
tectate. General body color brown with dark brown speckles and marks; venter
of abdomen green with brown spots; hind tibia green and black.
The specklewinged grasshopper is a late-hatching species. First instars
begin to appear in mid-July in the mixedgrass prairie of eastern Wyoming
and in the shortgrass prairie of eastern Colorado. Hatching continues for
about a month. A laboratory study has revealed that females lay nondiapause
eggs that hatch in 40 days at 77°F. This study suggests that the species
has a one-year life cycle under favorable temperature regimes. On the other
hand, field studies on the plains of central Saskatchewan and in the mountains
of Colorado indicate a two-year life cycle. As with several other grasshopper
species, this grasshopper appears to have a one-year or a two-year life
cycle depending on the climate of its habitat.
The nymphs of this species develop relatively fast. In mixedgrass prairie
at altitudes of 5,000 feet, they become third instars by late August, and
fourth and fifth instars by late September. The majority are in the fifth
instar, the stage that overwinters, by October. At the onset of cold winter
weather they become dormant. Precisely where they seek shelter is unknown.
Nymphs have been shown to survive freezing at temperatures as low as -16°C.
Surface ground temperatures seldom get colder than this extreme. In winter,
during periods of mild weather, some nymphs become active and may even
molt to the adult stage.
The time of general metamorphosis to adulthood comes in early spring
and varies as a function of weather, latitude, and altitude. In the mixedgrass
prairie of eastern Wyoming, adults are present in April, but in high mountain
habitats of Colorado adults may not emerge until July.
Adults and Reproduction
Adults remain in the same general area in which they developed as nymphs.
Densities of the males and females are apparently high enough on the plains
to present no difficulty in mate location. In the mountains, however, very
low densities present a problem of mate location that is solved by the
aggregation flights of males. These flights are also made in all habitats
of the plains. At the peak of daily activity, males make aggregation flights
every three to four minutes.
Courtship is conducted on the ground. A male can detect a female from
a distance of at least 2 feet away. He moves toward her in a series of
spurt-runs; that is, he runs making several complete leg movements, then
pauses and stridulates emitting one to three chirps. When he approaches
within 1 inch of the female, he orients to her face-to-face. They wave
their antennae at one another and the male continues to chirp. Next, the
male moves to the female's side, then faces and sometimes butts her thorax.
The male continues chirping and places his front tarsus on her middle femur
and stomps the ground rapidly with his hind tarsi. He then produces a series
of four or five chirps and mounts the female from the rear. If he is accepted,
the pair copulates. A receptive female may actively solicit attention from
a male by presenting her side, lowering the near hindleg, and raising both
the opposite hindleg and the tegmina, which exposes the whole abdomen.
One successful copulation of a pair was observed to last 23 minutes.
A gravid female selects bare ground when she is ready to oviposit. She
bores more than 2 inches into the soil and deposits a clutch of 20 to 21
eggs. After extracting her abdomen, she covers the hole by pulling debris
over the pod and tamps it down with her ovipositor. The eggs are light
brown to brown, and range in length from 4.5 to 5.2 mm (Fig.
10). Pods are long and usually break in extracting them from the soil.
One entire pod measured one and five-eighths inches long. Neither the potential
nor realized fecundity of this grasshopper is known.
Recorded populations of the specklewinged grasshopper have been small in
all habitats. Densities have ranged from 0.05 to 0.1 adults per square
yard in desert, northern mixedgrass, and shortgrass prairies. Populations
on the high altitude mesa of the Gunnison River in Colorado tend to gather
in clusters, occupying 200-400 feet diameter areas within an apparently
suitable and much larger habitat. Twenty to 40 adults per acre is the usual
density; seldom do densities reach 120 adults per acre even in the clusters.
In 1970, populations residing on the mesa above 9,200 feet crashed, but
populations at lower altitudes were nearly normal. It is likely that an
unusually cold winter killed the nymphs but not the diapausing eggs, which
hatched and allowed normal population densities of nymphs in August and
September 1970. A small number of nymphs in 1971 indicated there was no
recovery of the 1970 brood. Causes of population fluctuations at lower
altitudes east of the Rocky Mountains have not been studied.
Of biological interest is the geographic isolation of populations with
red or yellow wings. Specific color morphs are associated with particular
geographic regions, and between these regions narrow zones of hybrids and
mixed colors exist. Predominantly redwinged populations occupy the high
plains east of the Rocky Mountains. In central Colorado, yellow morphs
occupy isolated grassland habitats of pinyon-juniper and high coniferous
Because of the generally low densities of the specklewinged grasshopper,
few observations have been made of its daily activities. Apparently the
adults rest horizontally on the ground at night, their body temperatures
declining to the low ambient temperatures of spring. Immobile at dawn,
they begin to stir as the sun rises and then bask, orienting their sides
to the warming rays. At a soil surface temperature of 57°F they are
able to jump but not fly to avoid an intruder. Flight becomes possible
at soil surface temperatures a few degrees above 60°F. Feeding begins
around 10 a.m. and oviposition around 11 a.m. (MDT). In montane habitats
the conspicuous spontaneous flights of males peak between 10 a.m. and noon.
High temperatures suppress activity. Whenever the soil surface temperature
reaches 105°F, individuals either assume a stilt posture (legs extended
to lift the body off the ground) or move on the ground to the shade of
plants. Even without extreme heat, activity in the afternoon subsides.
One female was discovered resting horizontally on the ground in a nonbasking
orientation at 2:40 p.m. More observations on the behavior of this grasshopper
are needed to provide a complete picture of its daily activities.
Alexander, G. and J. R. Hilliard, Jr. 1969. Altitudinal and seasonal distribution
of Orthoptera in the Rocky Mountains of northern Colorado. Ecol. Monogr.
Gillis, J. E. and K. W. Possai. 1983. Thermal niche partitioning in
the grasshoppers Arphia conspersa and Trimerotropis suffusa
from a montane habitat in central Colorado. Ecol. Entomol. 8: 155-161.
Pfadt, R. E. and R. J. Lavigne. 1982. Food habits of grasshoppers inhabiting
the Pawnee site. Wyoming Agr. Exp. Stn. Sci. Monogr. 42.
Pickford, R. 1953. A two-year life-cycle in grasshoppers (Orthoptera:
Acrididae) overwintering as eggs and nymphs. Can. Entomol. 85: 9-14.
Schennum, W. E. and R. B. Willey. 1979. A geographical analysis of quantitative
morphological variation in the grasshopper Arphia conspersa. Evolution
Willey, R. B. and R. L. Willey. 1969. Visual and acoustical social displays
by the grasshopper Arphia conspersa (Orthoptera: Acrididae). Psyche
Next Species in Subfamily: Arphia pseudonietana
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