Kiowa grasshopper (Trachyrhachys kiowa)

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Trachyrhachys kiowa
Other common names
Ash-brown grasshopper
Taxonomic classification
Suborder:	Caelifera
Family:	Acrididae
Subfamily:	Oedipodinae
Tribe:	Psinidiini
Genus:	Trachyrhachys
Scientific name
Trachyrhachys kiowa (Thomas, 1872)
Geography
Native countries:
Guatemala Mexico Canada United States
Pest status
Known pest

The Kiowa grasshopper (Trachyrhachys kiowa), also commonly known as the ash-brown grasshopper, is a medium sized rangeland species found throughout North America most commonly in the west. This species is part of a subfamily of band-winged grasshoppers and is sometimes abundant enough to cause damage to rangelands.

Taxonomy

For full nomenclature and taxonomic details of this taxon, see Orthoptera Species File

Identification

The Kiowa grasshopper is a species of band-winged grasshoppers (subfamily Oedipodinae, family Acrididae), which are a distinctive feature of the semi-arid grasslands of North America. Anatomically, they are easily recognized by their large, lobed hindwings, often marked with spots or bands—features that set them apart from other grasshopper subfamilies. These hindwings also play a role in their behavior; many species produce a loud snapping crepitation during flight, which can be heard from across a pasture or field, making them identifiable even to those unfamiliar with insect taxonomy.

The band-winged grasshoppers form a distinct yet highly diverse group. While most species are harmless and should not be targets of control, the group also includes some of the most destructive pest species, like the clear-winged grasshopper. It ranges from delicate, inconspicuous grasshoppers to the largest and most visually striking ones in North America.

The Kiowa grasshopper is usually gray-brown, yellow-green, or tan with large spots or bands on its front wings. It has a raised ridge on its back with two notches and a stripe along the edge. Its head is relatively big with dark stripes under the eyes, and it has thin antennae and long wings. The back wings are often pale yellow with a broken black band, but in the north, they may be clear. Its back legs have long hairs, two pale yellow bands, and a dark inner area. The lower legs are blue or gray with tan areas and brown spots.

Nymphs are tan with dark markings or pale green with fewer marks. They have a straight face, a dark stripe on the head, and hairs on the back legs.

The Kiowa grasshopper resembles the finned grasshopper (Trachyrhachys aspera) and can be distinguished by the posterior angle of the lateral lobes of the pronotum. T. Kiowa has a posterior angle that is acute where T. aspera is at an almost right angle.

Identification details

The Kiowa grasshopper is generally grayish-brown, greenish-yellow, pale green, or tan, with large spots or bands on the forewings. The pronotum has an elevated ridge with two notches. A tan or gray stripe typically lines the posterior edge of the pronotum, though it appears green in a few rare individuals. The face is large and usually marked with dark stripes under the eye. Antennae are slender and forewings are long. Two or three large dark brown marks can be found in the middle of the tegmen, these markings get more abundant near the end. Hindwings are variable colors, often pale yellow with an incomplete black band . It is also reported that their hindwings contain no color in northern regions and usually lack markings.

There is a fringe of long hairs on the lower carina on the hind femur. The hind femur also contains two pale yellow bands, found near the knee and in the center of the femur. The inner medial area is generally dark brown or gray. Their hind tibia is blue or gray , with the inner side being the most distinctly blue, with the proximal end being more tan. This tan proximal area usually contains brown spots or markings.

Kiowa grasshopper nymphs are typically tan with dark brown markings, though some pale green ones have fewer but more distinct markings. They can be identified by their nearly vertical face and a thin dark stripe across the top of the head, between the eyes. Notably, they have fringe hairs on their hind femur, most visible in the 3rd and 4th instar stages.

Featured identification resources

• 
  Band-winged grasshoppers of the Canadian Prairies and Northern Great Plains
• 
  ARS species fact sheet Kiowa grasshopper
• 
  Pest grasshoppers in Oregon
• 
  Common Wyoming Pest Grasshoppers

All identification resources

Title	Author(s)	Year	Geographic purview	URL
Common Grasshoppers of Montana Cropland and Rangeland	Montana State University			View URL
A Manual of the Grasshoppers of New Mexico	New Mexico Cooperative Extension Service,D.B. Richman, D.C. Lightfoot, C.A. Sutherland and DJ. Ferguson	1993		View URL
Grasshopper investigations on Montana rangelands	Montana State University,Norman L. Anderson and John C. Wright	1952		View URL
Orthoptera of Northern Great Plains	North Dakota State University	2007
Hopper helper	Wendal Cushing			View URL
The grasshoppers of Nebraska	Animal and Plant Health Inspection Service,Mathew L. Brust, Wyatt Hoback and Robert J. Wright	2009		View URL
Common Wyoming pest grasshoppers	University of Wyoming,Scott Schell and Alexandre Latchininsky,B.A. Shambaugh			View URL
Field guide to some of the common grasshoppers of the Front Range of Colorado	University of Colorado			View URL
Montana.gov Orthoptera Field Guides				View URL
Field Guide to Common Western Grasshoppers	United States Department of Agriculture,Robert E. Pfadt	2002
Grasshoppers of the Western United States	United States Department of Agriculture			View URL
ARS grasshopper species fact sheets	Agricultural Research Services and United States Department of Agriculture	1994
Pest Grasshoppers of the West	University of Wyoming	2005		View URL
The Grasshoppers of the Western U.S. Lucid mobile app	APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture and Center for Plant Health Science and Technology of the USDA	2016
Rangeland Grasshopper Management	University of Wyoming,Jeffrey Lockwood and Scott Schell	1993

Distribution

The Kiowa grasshopper is abundant throughout the United States, less so in southern and New England states. This species is also found in southwestern Canada and throughout Mexico.

Biology

The kiowa grasshopper has one generation per year. Hatching begins around mid June, lasting two to four weeks. The nymph period lasts around 27 to 53 days, with development requiring 5 instars. Adults are found from June to November. Male Kiowa grasshoppers court females on the ground using single stridulating strokes of their hind legs and tap the female's head with their antennae before mounting. Females lay 8–10 eggs in bare soil near vegetation. The eggs are brown ors tan and pods contains eight to ten eggs, with dimensions around 4.4 to 5 mm in length. Eggs start developing in the summer when they are laid and continue growing until they enter diapause. Around spring, development resumes until the embryos fully mature and hatch.

Kiowa grasshoppers rest flat on the ground at night, even in cool temperatures. After sunrise, they start basking by turning their bodies to face the sun and exposing their abdomen to warm up. If it gets too hot (around 130°F), they move into plants or shade to cool off. When it cools down again, they return to basking until sunset. Generally, these grasshoppers spend 37% of their time basking, 31% pottering, and 32% feeding.

Photos of this species

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  Trachyrhachys kiowa
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  Trachyrhachys kiowa
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  Trachyrhachys kiowa

Habitat and ecology

T. kiowa lives in mixedgrass, shortgrass, and desert prairies, and is typically found in barren or sparsely vegetated microhabitats, often near low grass clumps. It frequently occurs in gravel pits, roadsides, rocky slopes, and open, sandy upland fields with patchy grass. It is also considered a pest in crested wheatgrass pastures. Its gray or tan coloring allows it to camouflage well against pale soils. T. kiowa eats almost exclusively grasses, with a strong preference for blue grama (Bouteloua gracilis), a key host plant in shortgrass and mixedgrass prairies. Other food plants include needleandthread, western wheatgrass, Kentucky bluegrass, threadleaf sedge, needle-leaf sedge, Penn sedge, sunsedge, sixweeks fescue, and sand dropseed. Nymphs don’t eat plant litter, and adults rarely do. They feed from the tip of a plant downward. On grasses like blue grama, they may feed on lower green leaves or pull higher leaves toward themselves using their front legs, while supporting themselves with their middle and hind legs. In tallgrass prairies, they move to areas with shorter, sparser grass such as hilltops or disturbed ground. Adults may also feed on small lichens that grow in mats on the soil surface. T. kiowa is a strong flier. When disturbed, it makes short, dodging flights with soft crepitation sounds. It may fly in straight or curved paths and often lands sideways, facing away from the threat.

Pest status

T. kiowa presents an occasional threat to grasslands in the western US states. In mixed grass prairies, Kiowa grasshopper populations usually stay low. However, under the right conditions, their numbers can suddenly surge, tripling or even increasing sevenfold in a year, especially when other grasshopper species like the bigheaded and white whiskered grasshoppers are also abundant. For this reason, it is one of the top dozen species monitored by USDA Animal and Plant Health Inspection Service (APHIS) because of its impact on rangelands.

Management

The main strategy for managing grasshopper outbreaks on rangelands in the United States involves the use of insecticides applied via all-terrain vehicle (ATV)-mounted or aerial sprayers. Recommended insecticides include diflubenzuron, malathion, chlorantraniliprole, various pyrethroids, and carbaryl. Applications are made either through full-area coverage or using a method known as Reduced Agent and Area Treatments (RAATs). RAATs are an integrated pest management (IPM) technique where insecticide rates are lowered from standard levels, and treated swaths are alternated with untreated ones, reducing total coverage to 50% or less. This method combines direct chemical control (killing grasshoppers in treated areas and as they migrate from untreated zones) with conservation biological control, allowing natural enemies in untreated areas to help suppress the population. This IPM strategy can cut both insecticide use and treatment costs by more than half. Control efforts typically achieve around 80% effectiveness, which is adequate to suppress most grasshopper populations. The insect growth regulator diflubenzuron has shown particular success in RAAT applications due to its long-lasting residual toxicity, which persists for about three weeks.

Associated organizations

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Resources

Title	Author(s)	Year	Geographic purview	URL
Common Grasshoppers of Montana Cropland and Rangeland	Montana State University			View URL
A Manual of the Grasshoppers of New Mexico	New Mexico Cooperative Extension Service,D.B. Richman, D.C. Lightfoot, C.A. Sutherland and DJ. Ferguson	1993		View URL
Grasshopper investigations on Montana rangelands	Montana State University,Norman L. Anderson and John C. Wright	1952		View URL
Orthoptera of Northern Great Plains	North Dakota State University	2007
Hopper helper	Wendal Cushing			View URL
The grasshoppers of Nebraska	Animal and Plant Health Inspection Service,Mathew L. Brust, Wyatt Hoback and Robert J. Wright	2009		View URL
Common Wyoming pest grasshoppers	University of Wyoming,Scott Schell and Alexandre Latchininsky,B.A. Shambaugh			View URL
Field guide to some of the common grasshoppers of the Front Range of Colorado	University of Colorado			View URL
Montana.gov Orthoptera Field Guides				View URL
Field Guide to Common Western Grasshoppers	United States Department of Agriculture,Robert E. Pfadt	2002
Grasshoppers of the Western United States	United States Department of Agriculture			View URL
ARS grasshopper species fact sheets	Agricultural Research Services and United States Department of Agriculture	1994
Pest Grasshoppers of the West	University of Wyoming	2005		View URL
The Grasshoppers of the Western U.S. Lucid mobile app	APHIS PPQ Science & Technology Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture and Center for Plant Health Science and Technology of the USDA	2016
Rangeland Grasshopper Management	University of Wyoming,Jeffrey Lockwood and Scott Schell	1993

Specimen contributors for this species

Bionomia links specimen records in GBIF to the people who collected and identified them. Each list shows the top 20 for this species. Read more…

Collected by

People who collected specimens of this species in the field.

• Charles Hart — 3 specimens collected
• Shigetsura Shiga — 2 specimens collected
• Theodore Henry Frison — 1 specimen collected

• Barnard Burks — 1 specimen collected
• Selim Peabody — 1 specimen collected
• Carlos Gerardo Velazco-Macías — 1 specimen collected
• Austin Kelly — 1 specimen collected

Identified by

People who determined the taxonomic identity of specimens of this species.

• Tyler Grant — 25 specimens identified