Montana Field Guide

The following comes from Hebard (1928), Brooks (1958), Helfer (1971), Vickery and Kevan (1985), BugGuide (2007), Wikipedia (2020). This was a robust medium to large locust with long wings (tegmina) extending well beyond the abdomen tip. General color was brownish yellow to grayish, with contrasting black markings on the head and lateral lobes of the pronotum. The hind tibia was blue or dark red.

Fascinating resource online here: The Locust Plague in the United States published 1877.

Hatching occurred from mid-May to early June. Adults were reported from July to early October.

The body length to end of forewings of males was 25mm and females 28mm. Head to wing tip 30 to 36+ mm. The long wing was conspicuously spotted and extended beyond the apex of the hind femur 4.5 to 10 mm (Hebard 1928, Brooks 1958, Helfer 1971, Vickery and Kevan 1985, BugGuide 2007, and Wikipedia 2020).

Very similar to the present-day Migratory Grasshopper, (M. sanguinipes) and the Red-legged Grasshopper, (M. femurrubrum). It has even been suggested that M. sanguinipes is the non-migratory phase of M. spretus but has not been substantiated. Molecular studies suggest that M. spretus may be more closely related to the Bruner's Spur-throat, (M. bruneri) than to M. sanguinipes (Lockwood 2004, and Wikipedia 2020).

Breeding sites occurred along riverbanks, sunny upland slopes, and subalpine grassy areas. Its true habitat and breeding sites had been established high in the Rocky Mountains while it was still present. It is reported that the species descended from the mountains to the prairies in vast numbers only in certain years, especially in dry and drought seasons following westward wind currents. Outbreaks usually lasted for two consecutive years.

Consumed almost anything including barley, buckwheat, wheat melons, tobacco, strawberries, conifers, apple trees, fence posts, laundry hung out to dry, and even each other (Yoon 2002).

The following is taken from BugGuide (2007), Wikipedia (2020), and Vickery and Kevan (1985). It is believed to have bred continuously but only in favorable locations mostly in Montana and Wyoming. In its northern range, only one generation occurred each year. In Texas, a partial second generation had been reported. This species had sedentary and migratory phases. Eggs laid in prairie habitats usually did not thrive. Nymphs behaved gregariously and tended to march during the warm periods of the day, stopping during the evening and early morning. Marching swarms (“hopper bands”) as large as one mile across occurred in 1877. Migratory phases formed immense swarms across the Great Plains in the 1870’s. One swarm in 1875, called “Albert’s swarm) was estimated to 110 miles wide by 1800 miles in length, covering an area of 198,000 square miles-larger than the state of Colorado. This swarm was guessed to contain 12.5 trillion locusts.