Insect identification > Orthoptera > Grasshoppers

Grasshoppers


GrasshoppersFamily Acrididae (the grasshoppers). The insects belonging in this group are commonly called grasshoppers.

A few kinds when adult migrate, often in such enormous numbers as to look like clouds in the sky. These migrating species are sometimes spoken of as locusts.

Grasshoppers are feeders on grass and vegetation in general and are injurious, the amount of injury they cause varying with their abundance. Their antennae, shorter than the body, and their tarsi, consisting of three segments (only two in the fore- and middle legs of the grouse locusts) quickly distinguish them from the related family Tettigoniidae.

The pronotum is extended backward somewhat, and down on the sides of the prothorax almost to the base of the forelegs. In the female there is a short, stout ovipositor composed of four parts, and the rather narrow forewings, usually somewhat leathery in texture, cover the large, delicate hinder pair when these, folded in plaits, are at rest above and along the Some adults have only short wings and some sides of the body. none at all.

Most grasshoppers lay their eggs in the ground, usually in the fall, and these hatch the following spring. The female works its ovipositor into the soil a short distance, then pushes apart its four pieces and deposits its eggs in a cluster containing from 25 to perhaps 80 eggs, covered by a fluid which hardens and forms a protecting case or "pod". More than one pod may be formed by the same insect. The young, on hatching, work their way out of the ground and feed, molting several times, and becoming adult after 2 or 3 months.

Only a few of the kinds of grasshoppers found in the United States are sufficiently migratory in their nature to deserve the name "locust." During the period between 1860 and 1880, however, and to some extent since, inhabitants of the states west of the Mississippi River have at times suffered the entire, or almost entire, loss of their crops by the ravages of swarms of the Rocky Mountain locust (Melanoplus mexicanus Sauss.) which, breeding in immense numbers on the eastern slopes of the Rocky Mountains, upon maturity migrated eastward for food and stripped everything where they alighted.

Settlement of these breeding grounds, and cultivation, destroying the eggs, has reduced these migratory flights, but occasionally grasshoppers occur in destructive abundance, not only in the West but in all parts of the country wherever they become so plentiful as to lay large numbers of eggs in ground not cultivated, such as pastures. Under such conditions, a sudden, more or less local, outbreak of these insects may take place in the spring, the damage being caused in these cases at first by the feeding of the nymphs and later, if nothing is done, by the adults.

There are many kinds of grasshoppers in the United States. Among the more abundant, and therefore injurious, species may be mentioned the red-legged grasshopper (Melanoplus femur-rubrum De G.), about an inch long, its hind tibiae bright red; the California devastating grasshopper (Melanoplus devastator Scudd.), a little smaller, found in the Western states; the differential grasshopper (Melanoplus differentialis Thos.), about an inch and a half long, present nearly everywhere, but rare in the East; the two-striped grasshopper (Melanoplus bivittatus Say) about the size of the last, with two yellow stripes along its back, generally distributed except in the South Atlantic states; the lesser migratory grasshopper (Melanoplus atlanis Riley.), about an inch long, found nearly everywhere in the United States and frequently seriously abundant west of the Mississippi River; and the clear-winged grasshopper (Camnula pellucida Scudd.) which though small is often very injurious. It is found in all the Northern United States and has its hind wings clear and almost colorless, while its forewings are spotted with brown. All of these species attack various cereal and forage crops.

In the Southern and Western states are large, short-winged grasshoppers which are very stout and from their appearance and clumsy movements are called "lubber grasshoppers". They attack grass, alfalfa and other crops.

The Carolina grasshopper (Dissosteira carolina L.), one and a half inches or more in length, is gray or brown, varying somewhat with the color of the ground where it lives. It is most noticeable along roads and when it is startled into flight its black hind wings with yellow margins and the crackling sound often produced at such times are sufficient to attract attention. It is found throughout the entire United States.

In one section including the smallest grasshoppers, generally called "grouse locusts," some of which are less than half an inch in length, the pronotum is extended back to, or even beyond, the end of the abdomen and the forewings are reduced to mere stubs. The hind wings of grasshoppers are often brightly colored, yellow, red or black. Such species are rarely injurious. The legs also often show bright colors.

The sounds produced by grasshoppers are made in one or the other of two ways. In some species the hind legs are drawn up and down across the forewings, ridges on the inner face of the femur scratching against a heavy vein on the wing and giving a rasping sound. In others the sound is produced while flying. Here the front edge of the hind wing is struck against the under surface of the forewing, making a short, sharp sound, which, quickly repeated, gives a kind of "crackling." Apparently the organs of hearing are located on each side of the body just above the base of the hind leg. Each is a rather large, smooth disk, suggestive of an eardrum membrane, connected by nerve fibers with a small ganglion which in turn connects with the main nervous system.