Montana Field Guide

The following is taken from Hebard (1928), Brooks (1958), Helfer (1971), Capinera and Sechrist (1982), Otte (1984), Vickery and Kevan (1985), Capinera et al. (2004), Brust et al. (2008), and Scott (2010). This species may be found named in both the past and present literature as Trimerotropis campestris. This is a medium size, slender, brown, or gray grasshopper mottled with dark spots. Often the head and pronotum (thorax) are paler in color and without spots. The tegmina (forewings) bear irregular, undefined bands and extends beyond the abdominal tip. The disk of the hind wings is yellow with a wide dark band and long spur nearly reaching the wing base. The carina (ridge) on the dorsal surface of the pronotum is elevated and cut by 2 sulci (grooves). Outer face of the hind femur is faintly spotted or banded; the inner face is orange to red-orange with a black ring and knee. The hind tibia is orange to red.

Communicative behavior/Crepitation*
Both sexes crepitate in flight when disturbed. During display flights, solitary males produce a snapping sound. When courting a female, the males employ three signals: (1) bursts of vibratory stridulation with one femur, (2) femur tipping, and (3) trills of stridulation. In male-to-male aggressive encounters, they shake and tip their hind femurs (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.

This species overwinters in the egg stage. Nymphs occur in early June to early July, and adults from mid-July through September (Otte 1970, 1984, and Vickery and Kevan 1985).

The following comes from Hebard (1928), Brooks (1958), Helfer (1971), Capinera and Sechrist (1982), Otte (1984), Vickery and Kevan (1985), Capinera et al. (2004), Brust et al. (2008), and Scott (2010). The body length to end of forewings is 25-30 mm for males, and 28-40 mm in females.

The Campestral Grasshopper can be confused with two Montana Trimerotropis species: latifasciata and pristinaria. It can be separated from these two species by its undefined, faded edged crossbands on the forewings. This species is closely related to its congener, Say’s Grasshopper (Spharagemon equale), but separated by possessing a higher pronotal carina (ridge) usually cut by two sulci (grooves) (Otte 1984).

This species inhabits mountain meadows to elevations up to 10,000 feet, grasslands, some prairies, dry hillsides, and gravelly to rocky areas in parklands. Also favors wheatgrass-bluegrass habitats (Otte 1984, Vickery and Kevan 1985, Brust et al. 2008).

The food habits of this species are poorly known, but believed to feed on a mix of grasses, sedges, and some forbs, showing a preference for milkvetch, Astragaus sp. (Brooks 1958, Vickery and Kevan 1985, and Brust et al. 2008).

For courtship display refer to the “Communicative behavior/Crepitation” section above. Egg pods contain 14 tan, turning dark brown, eggs that are 5.9 mm long and 1.3 mm in diameter. Hatched nymphs pass through 5 instars before reaching the adult stage. In some areas of their geographical range this species may have a 2-year life cycle in mountain habitats. Little other detail has been observed or reported in the literature (Capinera and Sechrist 1982, Otte 1984, and Vickery and Kevan 1985).