Montana Field Guide

The following is taken from Fulton (1931), Alexander and Thomas (1959), Vickery and Kevan (1985), Bland (2003), and Himmelman (2009). The body color is dark brown, reddish brown to dull black with light buff brown stripes bordered ventrally with a dark strip on the lateral sides of the wings (tegmina). Black is more common in individuals at more northern latitudes. The head is not partially retracted into the front of the pronotum as occurs in Allard's Ground Cricket (A. allardi), and is striped with 4 or 5 yellowish to dark colored longitudinal dark stripes, hence its common name.

Calling song description
The following comes from Alexander and Thomas (1959), Fulton (1931 and 1933), Elliott and Hershberger (2007), Himmelman (2009), Morris and Morris (2004), and Walker's SINA website (2020). The Allard's Ground Cricket (A. allardi), and the Striped Ground Cricket, A. fasciatus, are persistent singers both day and night. As in other crickets, the songs are produced only during the closing of the wings. The song has been described as “a regular series of high-pitched, metallic chirps or buzzes given at a rapid rate (other authors describe it as “a high, burry chit…chit…chit”). The pulse rate depends upon the ambient temperature. When singing, the male raises his wings (tegmina) about 45-degrees to the body, and spreads and vibrates them. Like most crickets, the right tegmen is the uppermost and the two tegmina are not identical. The right is darker in color and has a rougher surface. The left possesses only a narrow-raised edge on the inner margin where it comes in contact with the stridulatory file of the right tegmen. There are two variations of the mating song.

This species overwinters in egg stage. Nymphs hatch in June, maturing to adults by mid-July to early August, to late September. They usually disappear before the first frost (Vickery and Kevan 1985).

The following is comes from Fulton (1931), Alexander and Thomas (1959), Vickery and Kevan (1985), and Bland (2003). The body length for males is 7-10 mm and females 8-11 mm. The pronotum (thorax) is barrel-shaped, with the head and dorsal anterior and posterior margins are equal in breadth for short-winged (brachypterous) forms (the most common in this species). Long-winged forms (macropterous) can occur where the posterior pronotum edge is wider. In female short-winged forms, the tegmina covers about half of the abdomen length, and in males it covers about two-thirds of the abdomen. In long-winged females, the tegmina extends to the tip of the ovipositor, and the hind wings of males extend beyond the tip of the abdomen and cerci. The female ovipositor is 5.9 (<6)-10 mm. It is nearly straight with a slight upward curve, the tip is not swollen but tapering, and the dorsal teeth are short and evenly spaced. The male stridulatory vein is always less than 1 mm long (commonly less than 0.9) and less than one-third as long as the width of the head behind the eyes. It possesses 106-128 teeth with an average of 117. Two middle tibial spurs are unequal (see red arrow in drawing).

This species is easily confused for small Field Crickets, Gryllus spp., but the two Montana Allonemobius species are much smaller. However, they too are easily confused and difficult to identify because they do not possess any single morphological character by which they can be easily separated. They can be distinguished by using combinations of such characters as length of female ovipositor, head banding intensity, and length and head width behind the eyes. Males of the species’ can be separated by measuring the length of the stridulatory vein and number of teeth on the file of the right tegmen viewed dorsally (compare “Diagnostic Characteristics” for the Striped Ground Cricket and the Allard's Ground Cricket (A. allardi)) (Alexander and Thomas 1959).

This species prefers more moist and wetter habitats than A. allardi, such as low-lying moist areas in grasslands, edges of ponds, streams, and wetlands (Bland 2003, Howard and Furth 1986, and Vickery and Kevan 1985).

The Striped Ground Cricket is omnivorous and similar to Allard's Ground Cricket (A. allardi). However, it appears that A. fasciatus individuals require feeding upon an equal amount of both plant and animal matter (Vickery and Kevan 1985).

Generally, the same mating and reproductive sequences as those as those of Allard's Ground Cricket (A. allardi). Prior to mating, the male faces the female and sings, using one of its two special mating songs, and performs a dance by jerking his body backward and forward without changing the position of his feet. Male and female touch their antennae, performing what is called antennation. The male’s genitalia are protruded, but his spermatophore does not form until a short time before mating. The male turns away from the female, drops the tegmina, and backs toward the female and at the same time raises one hind femur with the tibia closed upon it, and moves it so far forward that it is inverted. The female crawls over the top of the male and begins to bite the specialized “gift-producing” proximal spine on the tibia. This brings the female forward for the male to push his claspers into the opening between her ovipositor and subgenital plate to attach the spermatophore. The pair remain in this position for 15-25 minutes, all the time the female biting the spine. When the female leaves, the spermatophore is attached with a tube through which sperm will be delivered to her spermatheca. Later she removes it and eats it. Ground Crickets, Allonemobius spp., produce one generation per year (Fulton 1931, Fedorka and Mousseau 2002, and Mays 1971).