Montana Field Guide

The following is taken from Hebard (1928), Brooks (1958), Otte (1981), Capinera and Sechrist (1982), Vickery and Kevan (1985), McDaniel (1987), Pfadt (2002), Capinera et al. (2004), Brust et al. (2008), and Scott (2010). This is a medium-sized brown or greenish grasshopper with a large head and dark markings. The forewings have three dark bands, sometimes there are pale stripes along the dorsal edge, converging posteriorly when folded. The hindwings are transparent with a diffused smokey color at the outer third of the tip. The pronotum (thorax) carina is low and cut with one sulcus. The dorsal disk of the pronotum (thorax) bears a light-colored X-marking and linear dark stripes or triangular markings on the metazoan (area behind the sulcus). Females of this species are mostly green, retaining the dark markings of the forewings, but lack markings on the pronotal disk. The outer face of the hind femur has three dark markings. The inner face is pale, with a black area, ring, and knee. The hind tibia is blue, with a light ring near its base.

Communicative behavior/Crepitation*
Crepitation flights are frequent and made by solitary males at a rate of >62 pulses per second. Both males and females crepitate when disturbed with a distinctive buzzing sound. In courtship and aggressive encounters, males vibrate their hind femurs against their forewings producing chirping, trilling, and ticking sounds when the femurs are lowered with the left and right legs alternating making the ticking sound. Both genders perform femur-tipping. Males also use femur-shaking 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.

The Dusky Grasshopper overwinters in the egg stage. Nymphs begin to occur in early to mid-June. The nymphal period is relatively long, ranging from 56 to 66 days. Adults begin appearing in August to September, sometimes into early October (Otte 1984, Vickery and Kevan 1985, Pfadt 2002, Capinera et al. 2004, and Scott 2010).

The following comes from Hebard (1928), Brooks (1958), Otte (1981), Capinera and Sechrist (1982), Vickery and Kevan (1985), McDaniel (1987), Pfadt (2002), Capinera et al. (2004), Brust et al. (2008), and Scott (2010). The body length to the end of forewings is 16-24 mm for males, and 22-31 mm for females. The wings extend 1-4 mm beyond the abdominal tip.

This species could be confused with other Bandwinged Grasshoppers of similar size with transparent, smokey-colored hind wings, such as Clear-winged Grasshopper (Camnula pellucida) and Kiowa Grasshopper (Trachyrhachys kiowa).

The Dusky Grasshopper inhabits several grassland types: mixedgrass, shortgrass, and bunchgrass prairie, but is most abundant in mixedgrass prairie. It prefers habitats with a rich abundance of grasses and sedges, mixed with bare spots (Otte 1984, Pfadt 2002, and Brust et al. 2008).

The Dusky Grasshopper is primarily a grass feeder, preferring western wheatgrass (Elymus smithii) and needleleaf sedge (Carex duriuscula), but also consumes quackgrass (Elymus repens), prairie junegrass (Koeleria macrantha), sand dropseed (Sporobolus cryptandrus), little bluestem (Schizachyrium scoparium), side-oats grama (Bouteloua curtipendula), Kentucky bluegrass (Poa pratensis), foxtail barley (Hordeum jubatum) and timothy. In some areas, it has been considered a minor pest by feeding on alfalfa (Otte 1984, Pfadt 2002, and Brust et al. 2008).

Males make frequent crepitation flights to attract females. These flights also attract other males. Courtship and mating take place on the ground. When an individual, female or male, moves near, the courting male produces a burst of trill stridulations while motionless. Then he moves toward the individual making a single pulse of “ordinary” stridulation. If the individual is a receptive female, she will lower the hind femur closest to the courting male, spread it away from her abdomen and turn her genitalia toward the male as he mounts and copulates. If the attracted individual is a male, he will repel the courter with aggressive femur-tipping and shaking!

Females oviposit in bare ground interspersed with grasses. They test the soil several times by boring with their ovipositors before egg laying. The pods are about ¾ in. long, slightly curved, and contain 14 to 20 tan eggs, measuring 4-4.4 mm long. The hatching period is relatively long over a period of six to eight weeks, which is thought to be due to early or late egg laying in the fall and influenced by soil temperatures. The Dusky Grasshopper passes through 5 instars before reaching the adult stage (Otte 1970, and Pfadt 2002).