Kiowa grasshopper (Trachyrhachys kiowa)

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Trachyrhachys kiowa Kiowa grasshopper
Distribution
British Columbia, Alberta, Saskatchewan, Manitoba, Arizona, California, Washington, Oregon, Nevada, Idaho, New Mexico, Utah, Colorado, Wyoming, Montana, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, Minnesota, Iowa, Missouri, Wisconsin, Illinois, Kentucky, Tennessee, Indiana, Ohio, West Virginia, Virginia, Pennsylvania, Delaware, North Carolina
Taxonomy
Family:	Acrididae
Subfamily:	Oedipodinae
Genus:	Trachyrhachys
Additional resources
Full taxonomy at OSF

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.

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.

Identification

The Kiowa grasshopper is generally grayish-brown, greenish-yellow, 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. The Kiowa grasshopper resembles the finned grasshopper (Trachyrhachys aspera) and can be distinguished by the posterior angle of the lateral lobes of the pronotum. The Kiowa’s posterior angle is acute where the finned grasshopper’s is at an almost right angle.

Life cycle parameters

Instar	Color/ Description	Body length	Femur Length	Antennal segment number
1		4-4.3 mm	2.3-2.5 mm	9-11
2		4.9-5.9 mm	3.1-3.4 mm	12-13
3		5.8-7.9 mm	3.6-4.5 mm	14-15
4	Dark band on head broken and less distinct	7.6-12.1 mm	4.7-6.5 mm	16-18
5	Dark band on head broken and less distinct	11-16 mm	7.8-9.4 mm	20-21
Adult Males	Weight: 148 mg (dry: 44 mg)	15-18 mm	9.4-11.5 mm	21-23
Adult females	Weight: 303 mg (dry: 80 mg)	17-24 mm	12-14 mm	21-22

Identification resources

Name	Year published	Resource link	Descriptive keyword	Language	Geographic purview	Author	Year published
ARS grasshopper species fact sheets	1994	View	Management, Species identification	English		Agricultural Research Services, United States Department of Agriculture, Robert E Pfadt	1994
Common Wyoming pest grasshoppers		View	Life cycle, Species identification, Biodiversity, Grasshoppers	English		University of Wyoming, Scott Schell, Alexandre Latchininsky, B.A. Shambaugh
Field Guide to Common Western Grasshoppers	2002	View	Species identification	English		United States Department of Agriculture, Robert E. Pfadt	2002
Field guide to some of the common grasshoppers of the Front Range of Colorado		View	Agriculture, Behavior, Grasshoppers, Distribution, Species identification, Morphology, Photos, Biology, Overview	English		National Science Foundation
Grasshopper investigations on Montana rangelands	1952	View	case study, Species identification, Behavior, Ecology	English		Montana State University, Norman L. Anderson, John C. Wright	1952
Grasshoppers of the Western United States		View	Management, Species identification	English		United States Department of Agriculture
Hopper helper		View	Survey, Life cycle, Species identification, Integrated pest management	English		Wendal Cushing
Montana.gov grasshopper field guides		View	Species identification, Management, Biology	English
Orthoptera of Northern Great Plains	2007	View	Information hub, Species identification, Taxonomy, Map, Photos, Nymphs	English		North Dakota State University	2007
Orthoptera Species File		View	Species identification, Biology	English		Orthoptera Species File Online
Pest Grasshoppers of the West	2005	View	Management, Species identification	English		University of Wyoming	2005
The grasshoppers of Nebraska	2009	View	Species identification, Map, glossary, grasshopper development, Grasshoppers, Biology, grasshopper anatomy	English		University of Nebraska, Mathew L. Brust, Wyatt Hoback, Robert J. Wright	2009
The Grasshoppers of the Western U.S. Lucid mobile app	2016	View	Management, Species identification	English		USDA-APHIS-PPQ-Science & Technology-Insect Management and Molecular Diagnostics Laboratory (Phoenix Station), United States Department of Agriculture, Center for Plant Health Science and Technology of the USDA, University of Nebraska, Chadron State College	2016

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.

Habitat and ecology

T. kiowa is found in barren and sparsely vegetated microhabitats often close to low grass clumps. It eats almost exclusively grasses, and has a strong preference for blue grama grass (Bouteloua gracilis). Minor foods include needleandthread, western wheatgrass, sixweeks fescue, and sand dropseed. In tallgrass prairies, it tends to move to areas with short, sparse grasses, like hilltops or disturbed land. Nymphs don’t eat plant litter, and adults rarely do. They feed from the tip of a plant downward. On plants like blue grama, they may eat low-lying green leaves or use their front legs to pull raised leaves closer, supporting themselves with their mid and hind legs. T. kiowa is a strong flier. When threatened, they make short evasive flights with soft crepitation. They may fly in straight or curved paths and often land sideways, facing away from the threat.

Preferred habitat information

Habitats	Food sources	Environmental conditions
Mixedgrass, shortgrass, and desert prairies. Pest of crested wheatgrass pastures Ability to camouflage on gray and white soils Gravel pits; Roadsides; rocky slopes; open, sandy upland fields (patchy grass)	Graminivorous and mainly feeds on forage grasses and sedges Prefers: short grasses such as Blue grama Key host plant in shortgrass and mixedgrass prairies is blue grama Western wheatgrass, Needleandthread, Kentucky bluegrass, threadleaf sedge, needle-leaf sedge, Penn sedge, sunsedge Adults may feed on small lichens attached in mats on soil surface	Nymphs develop more slowly in colder climates, and faster under warmer climates Basking continues until 10-11am DST Feeding behavior exhibited between 9am to 11am on warm and clear days 80 F- 90 F: most time spent on the ground

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.

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