Montana Field Guide

The following comes from Brooks (1958), Helfer (1971), Vickery and Kevan (1985), Bland (2003), and Scott (2010). An exceedingly small grasshopper with a long, pointed roof-like pronotum extending posteriorly beyond the abdominal tip. Body color is variable grayish to reddish brown, sometimes darker and often with a dorsal median longitudinal whitish stripe. This species is more frequently attracted to lights at night than other species of Tetrix.

The following is taken from Brooks (1958), Helfer (1971), Bland (2003), Scott (2010), and Vickery and Kevan (1985). Usually overwinters in the adult stage or as a late-stage nymph. Eggs are laid in May to June, the nymphs reaching the adult stage in fall. Adult populations decline in late August and September as these overwintered survivors die, and peak again in August and September as the new generation of nymphs mature. In some areas, this species is sometimes collected throughout the year, but generally found from mid-March to mid-September.

The following comes from Brooks (1958), Helfer (1971), Vickery and Kevan (1985), Bland (2003), and Scott (2010). The body length to end of forewings ranges from 7 to 12 mm for both males and females. However, females tend to be larger than males as measured by the length of the pronotum, which for males is 10 mm to 10.5 mm and females 11.9 to 12.5 mm. The middle leg femur is slender, measuring 3.8 to 1.7 times as long as broad. This species, as well as other Tetrix species are quite variable in color patterns due to polymorphism, the occurrence of genetically different forms of individuals within the same species or interbreeding population.

Could be confused with the Striped Ground Cricket (Allonemobius fasciatus), which possess an extended wing “look-a-like” to T. subulata’s pronotum. Compare with the other two pygmy grasshoppers occurring in Montana. Refer to Ornate Pygmy Grasshopper (Tetrix ornata) and Brunner's Grouse Locust (Tetrix brunnerii) for diagnostic characteristics for positive identification.

The Slender Grouse Locust frequents moist sandy habitats along streams, pond and lake margins, marshes, and bogs. It is occasionally found in drier cultivated areas and forests (Bland 2003, Brooks 1958, Brust et al. 2008, Hebard 1928, Helfer 1971, Hochkirch et al. 2000, and Vickery and Kevan 1985).

The Pygmy Grasshoppers specialize in feeding on the lower plants such as algae, mosses, fungi and lichens, but also, humus and detritus. Grasses and forbs are only consumed at the sprouting state when the leaves are small and tender (Hochkirch et al. 2000).

The following comes from Forsman (2018), Hochkirch et al. (2000), and Vickery and Kevan (1985). The mating strategy of the Slender Grouse Locust is polyandrous, in which the female mates with more than one male during the breeding season. In one study, 60 females were presented with 4 different males. No female mated only with just one male, whereas 8 females mated with 2 different males, 27 females mated with 3 different males, and 25 females mated with all 4 males. This strategy appears to be the sexual modii operandi of many, if not all, Tetrix species. Females survive one reproductive season and produce multiple pods of eggs consisting of up to 35 eggs per pod. Male nymphs pass through 5 instars and female nymphs pass through 6 instar stages before reaching the adult stage. Intraspecific variability is huge within Tetrix species in their morphology, color and pattern, physiology, behavior and life-history, even within individuals in a population.