Montana Field Guide

The following is taken from Hebard (1928), Helfer (1971), Morris and Gwynne (1978), Vickery and Kevan (1985), Capinera et al. (2004), and Scott (2010). The genus Cyphoderris is represented by two species in Montana, the Great Grig (C. monstrosa) and the Buckell’s Grig (C. buckelli). They are short-winged (tegmina) and flightless. The female wings are reduced to small oval lobes, and male wings are well developed for loud stridulation (“singing”). The Hump-wing Grigs are small to medium sized, robust, and bear similar body colors with contrasting black markings.

All Cyphoderris species are believed to overwinter concealed as a nymph, emerging in late spring to early summer when they become an adult in June, and remain active to November or the onset of cold weather (Morris and Gwynne 1978, Vickery and Kevan 1985, and Scott 2010).

The following comes from Hebard (1928), Helfer (1971), Morris and Gwynne (1978), Vickery and Kevan (1985), Capinera et al. (2004), and Scott (2010). The body size for males and females is 17 mm to 26 mm. The most prominent morphological identification features for this species is by examining the shape of the “sternal process” of the males’ genitalia on the 9th abdominal segment (see illustration) which lacks the ventrally-directed, hammer claw-like process and the Ander’s organ of its congener C. monstrosa.

The two species of Cyphoderris occurring in Montana are easily confused at first glance. There is also a third North American Grig species, the Sagebrush Grig (C. strepitans), which occurs only along the Rocky Mountain front of Wyoming and Colorado. Grigs can also be confused with the Decticids—the Shield-backed Katydids (Helfer 1971, Morris and Gwynne 1978, Vickery and Kevan 1985, and Scott 2010).

The Buckell’s Grig prefers dry forests dominated by Ponderosa pine (Pinus ponderosa) or Douglas fir (Pseudotsuga menziesii), at higher elevations (Helfer 1971, Morris and Gwynne 1978, Vickery and Kevan 1985, Capinera et al. 2004, and Scott 2010).

This species feeds nocturnally on forest understory plant flowers such as Serviceberry (Amelanchier), Arrowleaf Balsamroot (Balsamorhiza sagittata), and Oregon-grape (Berberis). Sometimes consumes fruit and other insects (Morris and Gwynne 1978, and Vickery and Kevan 1985).

The following is taken from Morris and Gwynne (1978), Vickery and Kevan (1985), and Morris et al. (1989).The males of this species typically call (stridulate) from low shrubs, sagebrush, and small understory trees about knee height (1 meter) from the ground. Otherwise, essentially the same as C. monstrosa.