Thursday, April 25, 2013

Speckle-winged Grasshopper

It is “OrThoptera Thursday,” and time to introduce you to a common springtime grasshopper, the Speckle-winged Grasshopper. It goes by Arphia conspersa in scientific circles.

Ordinarily, I would be seeing fair numbers of this insect by now, and indeed they are slowly becoming more abundant as the weather warms from an unseasonably cold early spring here along the Front Range of Colorado. Warmer enclaves have more activity, such as around Pueblo and CaƱon City. Last year I saw adults of this species on February 29, but then again we hardly had a winter.

Arphia conspersa is very widespread in its distribution, occurring from the Great Plains westward, north to central Alaska and south to central Mexico. It exploits a variety of habitats, from meadows up to 11,000 feet in elevation to desert canyons. Pastures, open fields, and vacant lots are where one is most apt to encounter it, even in highly urbanized areas.

Identifying the Speckle-winged Grasshopper can be surprisingly difficult because there is so much variation from one individual to the next. The overall color may be brown or grey with varying degrees of darker mottling. Many specimens sport a bright yellow “racing stripe” down the back when the wings are folded at rest. The tibia (“shin”) of the hind leg is often bright yellow (as can be the abdomen of males), but the tibia is usually concealed under the edge of the femur (“thigh”) unless the grasshopper is walking.

This species is one of the “band-winged grasshoppers,” named for the pattern on the hind wing. Unfurled, the hind wing is brightly-colored at the base, with a dark submarginal band across the outer reaches. The hind wing of Arphia conspersa may be colored yellow, orange, red, or even pink, but is only visible during the short flights made by the insect.

Males of the Speckle-winged Grasshopper are more likely to be heard than seen. Part of the courtship involves what are called “appetitive” or “crepitation” flights. The male purposely flies a short distance, making a loud crackling sound at will in the process. This visual and audible display apparently attracts the attention of the female.

A male can detect a female from a distance of at least two feet when both are on the ground. Considering how incredibly well camouflaged these insects are, that is no mean feat. He will approach by running, stopping and stridulating, and then repeating the process until he is next to his prospective mate. Stridulating is accomplished by rubbing the inside of the hind femur against ridges on the folded front wings. A faint chirping noise is generated by stridulating. Once in close proximity, the male orients to the female face-to-face, and they wave their antennae at each other. More complexities then ensue before she decides whether to accept his advances.

Mated females select patches of bare earth in which to lay their eggs. The abdomen of the female is capable of telescoping at least two inches while inserted into the ground. At that depth she deposits a pod of about twenty eggs.


female ovipositing in soil

Nymphs of Arphia conspersa begin hatching from the eggs in about mid-July, and go through a total of five instars (an instar is the period between molts) before reaching adulthood. The nymphs typically get to that fifth instar in late autumn, then overwinter. Exactly how they manage to survive is something of a mystery, but experiments have shown at least some specimens can withstand temperatures of -16°C for short periods.


nymphs

The fact that this is one of the few larger grasshoppers to be found as an adult in early spring makes its identification a bit easier. There are simply fewer similar species to confuse it with. Thankfully, this insect is never abundant enough to be a pest, either, even though it certainly consumes a fair amount of forage in the form of grasses and sedges.

Source: Branson, David, et al. 1994. “Speckle-winged Grasshopper, Arphia conspersa Scudder,” Wyoming Agricultural Experiment Station Bulletin 912.

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