Aeoloplides turnbulli (Thomas)
Wyoming Agricultural Experiment Station Bulletin 912
Species Fact Sheet
by Robert E. Pfadt
Geographic range of Aeoloplides
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The Russianthistle grasshopper enjoys a wide geographic range in western
North America from southern Canada to northern Mexico. It inhabits
desert shrub sites, local alkali flats vegetated with saltbush and
black greasewood, and grasslands, where it does not feed on grasses
but relies on the presence of host forbs, species of the goosefoot
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Depending on the vegetation of its habitat or the kind of crop
growing nearby, the Russianthistle grasshopper is either a beneficial
or a pest species. In western Kansas in 1938, outbreak populations
caused severe damage to sugar beets. Two years later during the
same outbreak, numerous individuals invaded wheat fields in late
June but caused no damage to the crop because of an abundant supply
of green Russianthistle, a preferred host plant.
Populations that irrupt in desert shrub communities, such as the
Big Horn Basin, Wyoming, damage valuable forage chenopods including
Gardner saltbush, fourwing saltbush, and winterfat. Livestock, especially
sheep, select these shrubs for feed during winter months when grasses
and forbs are scarce or absent.
This grasshopper plays a beneficial role when populations inhabit
patches of kochia, Russian thistle, or lambsquarters growing on
disturbed land and in field borders and roadsides. The grasshoppers
feed on the growing points of these plants, reducing seed production
The Russianthistle grasshopper is in the largest third of rangeland
grasshoppers. Live weight of males and females collected from a
desert shrub community in the Big Horn Basin, Wyoming, with Gardner
saltbush the chief host plant, averaged 296 mg and 548 mg, respectively
(dry weights: 94 mg and 175 mg, respectively). Live weight of males
and females collected from a disturbed site in southeast Wyoming
invaded by kochia averaged 242 mg and 462 mg, respectively (dry
weights: 76 mg and 146 mg).
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The Russianthistle grasshopper feeds on species of the goosefoot
family of plants (Chenopodiaceae). Principal host plants are shrubs
or stout herbs, which afford the grasshoppers both nutritious food
and roosting sites. Shrubs that serve commonly as host plants include
fourwing saltbush, Gardner saltbush, white sage, also called winterfat,
(Ceratoides lanata), and black greasewood, while stout herbs
include the weeds kochia, Russian thistle, and lambsquarters. The
latter plants frequently occur together in disturbed land providing
the grasshoppers with an opportunity for a mixed diet. Likewise,
in desert shrub habitats several chenopod species are usually present
in addition to the principal host plant. In a desert shrub site
of the Big Horn Basin, Wyoming, Gardner saltbush was the principal
host plant but other chenopods were available to the grasshoppers.
These were chiefly small annuals with five species sustaining grasshopper
damage: Atriplex argenta, A. powelli, A. suckleyi,
Sarcobatus vermiculatus, and Suaeda nigra. One species
showed no damage, the introduced Halogeton glomeratus. This
is unfortunate because this weed is very difficult to control and
is toxic to sheep due to its high content of oxalates.
Field observations and gut analyses indicate that the Russianthistle
grasshopper also feeds sparingly on several forbs belonging to at
least six plant families other than Chenopodiaceae.
The Russianthistle grasshopper's method of attacking its host plant
is notable for the selection of young tissue. From basking or roosting
positions on kochia or Gardner saltbush, the grasshoppers climb
to the growing tips to feed. There they consume young leaves and
other developing tissues. Timed feeding bouts of two adults took
six and seven minutes. In the desert shrub community of the Big
Horn Basin, where Gardner saltbush dominates and much bare soil
prevails, both nymphs and adults often come down to the ground during
the day. They do not, however, appear to feed on ground litter.
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Very little is known about the dispersal and migration of the Russianthistle
grasshopper. Two accidentals, a male and a female of the southern
subspecies, Aeoloplides turnbulli bruneri, were found in
the mountains west of Boulder, Colorado. One was an adult male taken
at 7,700 feet on 7 August 1933, the other an adult female taken
at 12,100 feet on 4 August 1960. Collection of these two provides
evidence for dispersal of the long-winged subspecies, A. t. bruneri.
Wings of the northern subspecies, A. t. turnbulli, vary
in length but are usually noticeably short of the end of the abdomen.
Compare Figure 7 of a female of the northern subspecies collected
in eastern Wyoming (Platte County) with Figure 8 of a female of
the southern subspecies collected in southeastern Colorado (Bent
County). The wings of adults of the northern subspecies that inhabit
the Big Horn Basin, Wyoming (Big Horn County) are even shorter,
falling short of the end of the hind femur by 3 to 6 mm. The hind
wings of the males averaged 8.8 mm long and of females 9.7 mm. In
spite of the relatively short wings and heavy weight, the adults
are able to fly. In flushed flight they travel an average distance
of 3.6 feet at heights of 4 to 6 inches. The flight is silent and
straight with the grasshopper usually landing face away from the
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Figures 1-5. Appearance
of the nymphal instars, their sizes, structures, and color
patterns. Notice progressive development of wing pads. BL=body
length, FL=Hind Femur Length. AS=number of antennal segments
First Instar: BL 3.8-4.9 mm FL 2.5-2.8 mm AS 12-14.
Second Instar: BL 5.6-7.1 mm FL 3.6-4.3 mm AS 15-17.
Third Instar: BL 7.7-8.5 mm FL 5.0-5.9 mm AS 18-20.
Fourth Instar: BL 10-13 mm FL 6.5-7.1 mm AS 20-22.
Fifth Instar: BL 14-17.3 mm FL 9-10.3 mm AS 22-24.
Figures 6-10. Appearance
of the adult male and 2 females, cercus, and egg pod.
Adult Male: BL 18-20.5 mm FL 10-11.2 mm AS
23-26. Northern subspecies A. turnbulli turnbulli
Adult Female: BL 18.8-25
mm FL 11-13 mm AS 23-25. Northern subspecies A. turnbulli
Fig. 8, BL 21-23.5
mm FL 11-12.5 mm AS 22-24. Southern subspecies A. turnbulli
Fig. 9, End of male
abdomen showing cercus and subgenital plate with subapical
Fig. 10, Egg pod and
exposed eggs in opened pod.
The Russianthistle grasshopper is a medium-sized robust species.
It has a distinctive color pattern of shades of tan with fuscous
markings (Figs. 6 and 7). The wings of the northern subspecies,
A. t. turnbulli, may be 2 to 4 mm short of the end of the
abdomen (and also the end of the hind femur, a less variable measurement).
The wings of the southern subspecies, A. t. bruneri, are
longer, surpassing the end of the abdomen (Fig. 8). Lateral light
bands mark the sides of the pronotal disk and are separated by a
broad fuscous band. The latter band is divided by the median carina,
which may be colored partly or entirely light tan. The hind femur
has three characteristic fuscous marks on the medial area. These
dark marks usually extend dorsally onto the upper marginal areas.
The hind tibia is usually medium blue with a pale tan annulus near
the base. The male possesses tiny furcula represented by minute
lobes, a subgenital plate with a conspicuous subapical tubercle,
and triangular slender cerci (Fig 9).
The nymphs ( Fig. 1-5)are identifiable by their structure, color
patterns, and shape.
- Head with face nearly vertical, head tan to pale tan or green
with several to many fuscous spots; compound eye with large pale
tan spots in brown reticulum; antennae filiform, first two segments
(scape and pedicel) pale yellow with several brown spots, rest
of segments (flagellum) fuscous, each with pale anterior annulus.
- Pronotum tan or green with several to many brown spots, median
carina pale contrasting with main color of disk, the pale line
extends onto abdomen; disk becomes distinctly wider posteriorly
(a diagnostic character).
- Outer medial area of hind femur uniformly tan or green with
several to many brown spots or with three fuscous markings, tan,
and spotted (Fig. 2). Hind tibia is green, blue or pale gray,
usually with brown spots.
- General body color tan or green.
Characters especially useful in identifying the nymphs are: 1.
the shape of the pronotal disk, which widens from front to rear,
2. most individuals heavily spotted brown or fuscous, 3. nymphs
are colored pale green, pale tan, or pale gray, 4. in tan or gray
nymphs, three characteristically shaped dark markings are usually
present on the medial and marginal areas of the hind femur (Fig.
1 and 2), in green forms, these markings are faint or lacking (Fig.
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The Russianthistle grasshopper is an early-hatching species. In
weedy roadside habitats of eastern Wyoming, first instars appear
as early as late April or the first of May along with the twostriped
grasshopper, Melanoplus bivittatus. In the desert shrub of
the Big Horn Basin, hatching may occur one to two weeks earlier.
The hatching period is extended, lasting from four to five weeks.
No study of egg development has been made.
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Both the male and female nymphs require five instars to develop
to the adult stage. Because of their nature to develop a robust
body, their early hatching in spring, and their habitual location
high on the host plant where ambient temperatures are lower than
on the ground, the Russianthistle grasshopper's nymphal period is
relatively prolonged ranging from 50 to 60 days.
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In the desert shrub habitat of the Big Horn Basin, adults may appear
as early as mid June, but in the weedy roadsides and disturbed sites
of southeastern Wyoming, adults of the Russianthistle grasshopper
do not appear until the last week of June. The processes of sexual
maturation and courtship have not been determined in this species.
The duration of copulation by a pair is unknown, but mating pairs
have been observed sitting on host plants and on the ground during
July and August from early morning until late evening. Attempts
at oviposition by two females were observed in the desert shrub
habitat of the Big Horn Basin. The first observation was made on
17 August 1993 from 1 to 1:07 p.m. DST when soil surface temperature
was 120°F, air temperature 82°F, and sky clear. The female was discovered
walking and hopping on the ground. After traveling a distance of
12 feet, she stopped and began to bore into bare ground
for several seconds, then withdrew her ovipositor and walked another
12 feet. When she stopped again at 1:05 p.m., she bore into
the soil for approximately one minute. She again withdrew her ovipositor
and walked. By this time she was some distance from the observer
and was lost to view. In the same desert shrub site another female
was observed attempting to oviposit on 19 August 1993 at 1:23 p.m.
DST when soil surface temperature was 121°F, air temperature 83°F,
and sky clear. After this female was discovered, she crawled 2 feet
into the shade of a clump of halogeton. She began to bore into the
soil at 1:23 p.m. and continued for four minutes until she was disturbed
by the observer and walked away, disappearing into the vegetation.
These two attempts at oviposition suggest that the Russianthistle
grasshopper oviposits in bare ground. The pods are stubby, 7/16
inch long, 3/16 inch diameter, and slightly curved. They have a
sloping cap and the top appears pinched (Fig. 10). A plug
of froth is lacking but reddish brown froth completely surrounds
the egg mass and the individual eggs. The eggs are light-reddish
brown or tan and 4.0 to 4.4 mm long. There are 12 to 18 eggs in
a pod. The fecundity of females is high. In Canada, six caged females
produced an average of 250 eggs each.
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Populations of the Russianthistle grasshopper develop in sites
with an abundant supply of host plants. Such habitats usually occur
in disturbed land, crop borders, weedy rangeland, and desert shrub
associations dominated by saltbush (Atriplex spp.). The high
fecundity of this species allows populations to irrupt during environmentally
favorable periods. Densities in farmyard patches of weeds, usually
less than an acre in size, may reach 100 or more young adults per
Outbreaks may occur in much larger areas such as the wheat-growing
region of western Kansas and eastern Colorado. During the drought
period of 1931-41, A. t. bruneri came into prominence in
1937. The grasshoppers hatched along the edges of wheat fields where
Russian thistles had grown profusely the previous fall. The species
became the dominant grasshopper in this area from 1938 to 1941 supplanting
the migratory grasshopper, Melanoplus sanguinipes, as the
most abundant species. In a 10 square mile study area of Finney
County, Kansas, the Russianthistle grasshopper averaged one young
adult per square yard in 1939. In 1940 the population more than
doubled, and in 1941 the population remained high early in the season.
During the latter half of May 1941, 150 late instar nymphs per square
yard were recorded. But in June an epizootic struck the population
and brought the outbreak to an abrupt end. Caused by an undetermined
species-specific pathogen, the disease almost completely obliterated
the Russianthistle grasshopper from the entire area.
Outbreaks of the northern subspecies, A. t. turnbulli, also
occur. In 1993 an outbreak of this grasshopper was discovered in
a desert shrub habitat of the Big Horn Basin, Wyoming. The vegetation
of the infested area, at least 10 square miles in extent, was dominated
by Gardner saltbush, a preferred host plant. High densities of this
grasshopper ranging from 8 to 13 young adults per square yard occurred
everywhere within the area. The adult population sustained a low
daily mortality rate of 5 percent. The outbreak has continued for
a minimum of two years, as high numbers were present in 1994.
Despite the prevalence of a variety of host plants (chenopods),
few rangeland sites of the mixedgrass prairie harbor populations
of the Russianthistle grasshopper. Only four sites out of 241 (1.7
percent) surveyed in eastern Wyoming in 1991 and only two sites
out of 42 (1 percent) surveyed in the mixedgrass prairie of Montana
in 1953 and 1954 contained this species. However, in 1991 in the
desert shrub of the Big Horn Basin, this species occupied 23 sites
out of 190 (12 percent) surveyed. Densities of grasshoppers in an
eastern Wyoming rangeland site with an abundance of host plants
of the Russianthistle grasshopper (Russian thistle, winterfat, and
slimleaf lambsquarters) were sampled for several years. This survey
revealed that for an eight-year period the populations of Russianthistle
grasshoppers fluctuated from less than 0.1 per square yard to 0.54
per square yard and that the species held a low rank of abundance
in the grasshopper assemblage in all years.
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The Russianthistle grasshopper is a phytophilous species
spending much time on its host plant. However, during daylight hours
in habitats of sparse vegetation with an abundance of bare soil,
the grasshoppers descend regularly to the ground. There they bask,
rest, crawl, and disperse short distances.
Extended observations of the species' behavior were made in a native
desert shrub habitat of the Big Horn Basin, Wyoming, where Gardner
saltbush served as its principal host plant. During the night nymphs
and adults usually rest vertically, head-up on the stems of this
shrub; a few take positions on ground litter underneath the shrub.
One hour after sunrise the grasshoppers resting on the host plant
begin to bask by adjusting their positions so that the rays of the
sun strike a side or their back. They may also lower a hindleg to
expose the abdomen more fully. A few individuals may jump to the
ground to bask. Basking lasts for about two hours, after which the
grasshoppers become active. Some may crawl to the top of
the plant to feed on the growing tips, some may undergo a molt,
some may jump from one stem to another, and many continue to roost
quietly. Eventually the majority leave the host plant and spend
time on the ground during the day until evening when they again
seek shelter of the host plant. On the ground they mix among themselves
and disperse short distances. Many mating pairs occupy both the
host plant and the ground surface. During five-hour periods of observation,
37 single adults and 12 mating pairs were noted on 21 July 1993
and 17 singles and 13 mating pairs on 17 August 1993. Only one attempt
at mating was observed; a female resting on saltbush was mounted
by a male on 17 August 1993 at 1:54 p.m. The encounter ended unsuccessfully
with no consummation of mating. In early afternoon females probed
the soil for oviposition but no actual laying of eggs was observed.
When soil surface temperatures are above 120°F during midday, grasshoppers
on the ground take evasive actions to prevent overheating. They
may directly face away from the sun and stilt, or they may crawl
and hop into the shade of vegetation or under the canopy of saltbush.
Because the grasshoppers located on the host plant are not subjected
to the high ground temperatures, they continue their activities
When temperatures cool in the afternoon the grasshoppers on the
ground become active again. Continued cooling of the habitat incites
the grasshoppers both on the ground and on the host plant to assume
basking orientations. Finally, close to sunset, the grasshoppers
seek shelter. Those on bare ground crawl to the saltbush host plant;
some rest on litter under the bush and many crawl up a stem and
rest within the canopy.
In dense stands of kochia and lambsquarters the behavior of the
Russianthistle grasshopper differs somewhat from that of the grasshoppers
occupying habitats with much bare ground. In dense vegetation the
grasshoppers roost all day, most vertically head-up on plant stems,
but some horizontally on leaves. Rarely coming down from their perches,
they carry out essential activities on the host plants - basking,
feeding, molting, and mating. Gravid females, however, are compelled
to descend to bare ground to oviposit into soil.
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Alexander, G. and J. R. Hilliard, Jr. 1969. Altitudinal
and seasonal distribution of Orthoptera in the Rocky Mountains of
northern Colorado. Ecol. Monogr. 39: 385-431.
Anderson, N. L. 1973. The vegetation of rangeland
sites associated with some grasshopper studies in Montana. Montana
Agr. Exp. Stn. Bull. 668.
Newton, R. C. and A. B. Gurney. 1956. Distribution
of range grasshoppers. Coop. Econ. Insect Report 6: 600.
Vickery, V. R. and D. K. McE. Kevan. A monograph
of the Orthopteroid insects of Canada and adjacent regions. Lyman
Entomol. Mus. and Res. Lab. Mem. 13 Vol 2: 740-745.
Wallace, H. S. 1955. Revision of the genus Aeoloplides
(Orthoptera, Acrididae). Ann. Entomol. Soc. Am. 48: 453-480.
Wilbur, D. A. and R. F. Fritz. 1942. An epizootic
among the thistle hoppers, Aeoloplus turnbulli bruneri. Caud.,
in Kansas. J. Econ. Entomol. 35: 109.
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