Montana Field Guide

The following is from Brooks (1958), Vickery and Kevan (1985), Pfadt (2002), Capinera et al. (2004), and Scott (2010). A small, short-winged grasshopper. Some individuals may have long wings which extend 2 to 4 mm beyond the abdomen tip. Body color is dark brown or grayish dorsally and bright yellow ventrally. The abdominal segments are black and ringed with bright yellow. A prominent whitish stripe angles downward on the side of the thorax behind the pronotum.

This species overwinters in the egg stage. Eggs generally begin hatching during the first week of June, but depends upon altitude, seasonal temperatures and precipitation. Adults occur from July to October, again subject to climatic and environmental factors (Pfadt 2002, Capinera et al. 2004, Capinera and Sechrist 1982).

The following is taken from Brooks (1958), Vickery and Kevan (1985), Pfadt (2002), Capinera et al. (2004), and Scott (2010). Body size of males is 14 to 19 mm and females is 19 to 25 mm. The outer surface of the hind femur is yellowish with dark chevron-like bands. The hind tibia is red with black spines. Wings are short, about the length of the pronotum, and oval, tapering to a blunt point.

The Dawson's Spur-throat Grasshopper is easily identified from other Melanoplus species due to its small size, short wings, black and yellow ringed abdomen and bright yellow center (Pfadt 2002).

The Dawson's Spur-throat Grasshopper inhabits grass prairies, shrubby brush and grass-forb park-like wooded areas with a preference for dry soils (Vickery and Kevan 1985, Pfadt 2002, Capinera et al. 2004)

Feeds mainly on forbs. Forty species of forbs in 13 plant families are consumed, including western ragweed (Ambrosia psilostachya), lupines, lead plant (Amorpha canescens), milkvetches, dandelions, asters, goldenrods, golden pea, legumes, alfalfa (Medicago sativa) and white clover (Trifolium repens) are also favored. Ten species of grasses (in small amounts) have been found to be consumed (Brooks 1958, Pfadt 2002, and Vickery and Kevan 1985).

Upon egg hatching, the nymphs pass through 5 instars and the development period can vary from 20 to 45 days depending upon environmental factors. Transformation to the adult stage continues for four to five weeks in mid to late August. Thus, the adult population consists of varying age classes. Time of attaining sexual maturity has not been studied, but courtship and copulation behaviors have been observed. A courting male produces bursts of vibratory leg stridulation, and when close to a female he makes a sudden jump on her back and continues to stridulate. If she is receptive, copulation begins. The pair can remain attached (in copulo) for a lengthy period, over 2 hours has been observed (Pfadt 2002)!