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Montana Field Guides

Kiowa Grasshopper - Trachyrhachys kiowa

Native Species

Global Rank: G5
State Rank: SNR


Agency Status
USFWS:
USFS:
BLM:


 

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General Description
The following is taken from Hebard (1928), Brooks (1958), Helfer (1971), Capinera and Sechrist (1982), Otte (1984), Vickery and Kevan (1985), Pfadt (2002), Bland (2003), Capinera et al. (2004), Brust et al. (2008), and Scott (2010). This is a small to medium-sized grasshopper and quite variable in color and markings across its geographical range. Generally, the body color is tan, but it can also be pale green with a conspicuous diagonal black stripe across the lateral side of the head below the eye. The eye often bears a light, diagonal stripe across its center. The tegmina (forewings) are long, extending well beyond the abdominal tip and have two to three large, dark spots centered in the middle and spotting at each end. The dorsal field can have either a pale streak which converges to a V-shape or be entirely pale. The hind wing is commonly clear with a short narrow black stripe on the anterior edge. On rare occasions some individuals in Montana may possess a tinge of yellow on the disk, bordered by an incomplete faded band. The pronotum (thorax) is elevated, bearing two knobs cut deeply by two sulci (grooves). The dorsal and posterior edges of the pronotum of some individuals can be bordered by a pale stripe. The inner face of the hind femur is pale with two black bands and knee. The hind tibia is pale blue or blue-gray with pale at the base.

Communicative behavior/Crepitation*
Crepitation in this species has not been observed, and most observations regarding behavior remain inconclusive. Femur-shaking and bursts of stridulation* have been observed, as has femur-tipping and striking the ground with the hind tibia during aggressive encounters (Otte 1970, 1984, and Vickery and Kevan 1985).

*Crepitation is the sound produced by grasshoppers making a clicking or snapping noise with their wings when in flight, during courtship, territorial encounters or being disturbed.

*Stridulation is rubbing one body part against another, usually the hind femur against the forewing in the case of the Band-winged Grasshoppers. This is often used for attracting a female during courtship (Otte 1970).

Phenology
This species overwinters in the egg stage. Nymphs begin to appear around the first half of June, the actual dates of hatching are dependent on the heat accumulation of the soil. Thus, their occurrence at a site may vary by 15 days between years and the nymphal period can last from 2 to 4 weeks. Adults occur from July to mid-October (Otte 1984, Vickery and Kevan 1985, Pfadt 2002, Capinera et al. 2004, and Scott 2010).

Diagnostic Characteristics
The following comes from Capinera and Sechrist (1982), Otte (1984), Pfadt (2002), and Scott (2010). The body length to end of forewings is 20-25 mm for males, and 23-30 mm for females. The posterior margin of the pronotum lateral lobe is often acute at a downward angle (see image). The ventral edge of the hind femur has a fringe of long hair, 3-4 mm in males, and 4-5 mm in females. This species could be confused with some species in the genus Trimerotropis.

Species Range
Montana Range Range Descriptions

Native
 


Range Comments
The Kiowa Grasshopper is the most widely distributed species of all the bandwings, extending from southeastern British Columbia, across the Prairie Provinces to southwestern Manitoba, southward through Mexico to Guatemala. From the west, eastern Washington, Oregon, and northeastern California, across the Rocky Mountains, Great Plains, the central states to Pennsylvania, angling southward to North Carolina. In Montana, it has been reported for 50 counties, but essentially occurs statewide (Vickery and Kevan 1985, Pfadt 2002, Capinera et al. 2004, and Scott 2010).

Observations in Montana Natural Heritage Program Database
Number of Observations: 41

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Inhabits a wide variety of grasslands dominated with short grasses and areas sparsely vegetated, especially those with an abundance of Blue Gramma (Bouteloua gracilis). It also inhabits roadsides, sagebrush steppe and overgrazed, disturbed sites (Otte 1984, Vickery and Kevan 1985, Pfadt 2002, Capinera et al. 2004).

Food Habits
The Kiowa Grasshopper feeds almost exclusively on grasses and sedges, Blue Gramma (Bouteloua gracilis), being its preferred food species, which can make up 84 to 100 percent of its diet. Other species consumed include substantial amounts of Western Wheatgrass (Elymus smithii), Needle-and-Thread (Stipa comata), Kentucky Bluegrass (Poa pratensis), Thread-leaved Sedge (Carex filifolia) and Needleleaf Sedge (Carex duriuscula) (Vickery and Kevan 1985, and Pfadt 2002).

Reproductive Characteristics
Courtship occurs on the ground, the male walking or hopping toward the female, making stridulating strokes with its hind femora. A receptive female is mounted by the male as he taps her head with his antennae. Copulation lasts from 25 to 40 minutes. Females deposit their eggs in bare ground close to vegetation and take 45 to 60 minutes to complete the task. The egg pods measure 28 mm long and contain 8 to 10 two-toned brown-and-tan eggs measuring 4-5 mm long by 1 mm in diameter, arranged in two columns and covered from the above with a froth plug. The outside of the pod is protected with a small amount of froth. This species produces one generation per year and females may produce only one pod during their lifetime. Nymphs pass through 5 instar stages before reaching the adult stage (Otte 1970, 1984, Vickery and Kevan 1985, and Pfadt 2002).

Management
The Kiowa Grasshopper is the only bandwinged species that is cited in the literature as being a “pest of economic concern.” It can reach outbreak populations in mixedgrass prairies, but in association with other species comprising 1 to 13 percent of the outbreak population. It is rarely dominant but can become the second most dominant within an outbreak assemblage. This species’ low reproductive rate may explain why it rarely reaches high population densities (Pfadt 2002, and Schell et al. 2005).

References
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Citation for data on this website:
Kiowa Grasshopper — Trachyrhachys kiowa.  Montana Field Guide.  .  Retrieved on , from