Carolina grasshopper

Appearance

The Carolina grasshopper, one of North America's largest grasshoppers, is a conspicuous species because of its size 32-58 mm, colorful wings, and habit of flying over dirt roads and other bare ground. The wingspread of the males measures 3 inches and that of the females 3 1/2 to 4 inches. The hind wings are black with a pale yellow margin. The tegmina are colored tan, brown, or gray matching the general body color and are faintly speckled.

The nymphs are identifiable by their color patterns, shape, and external structures.

- Head with face nearly vertical; antennae filiform, terminal segments dark, basal segments colored like body; lateral foveolae small and triangular.
- Pronotum with median carina strongly elevated and cut once.
- Hind femur with medial area evenly colored like body, may be spotted in instars IV and V; inner knee tan or fuscous, basal half of inner medial and lower marginal areas fuscous, distal half with two pale yellow transverse bands; hind tibia of instar I and II black with basal annulus pale yellow, hind tibia of instars III to V with variable patterns of tan, gray, and black; hind tarsus white or pale yellow except distal end fuscous.
- General body color tan, brown, or gray. Reddish in individuals developing on red soils.

Naming

Other Common Names
Road Duster
Black-winged Grasshopper
Quaker

Synonyms and other taxonomic changes
Gryllus (Locusta) carolinus Linneaus, 1758, described from Charleston, South Carolina
Acridium carolinum (Linneaus) De Geer, 1773
Locusta carolina (Linneaus) T.W. Harris, 1835
Dissosteira carolina (Linnaeus) S.H. Scudder, 1876
Acridium (Oedipoda) carolinum (Linneaus) S.H. Scudder, 1901

Distribution

Most of 48 United States except southern Florida, Gulf Coastal Plain, southwest Arizona, and bottom 2/3rds of California.

Behavior

The Carolina grasshopper, a ground-dwelling species, is active chiefly during daylight hours. Emerging from overnight shelters, both nymphs and adults bask in the morning sun for two to three hours beginning approximately two hours after sunrise. They turn a side perpendicular to the rays and lower the associated hindleg to expose the abdomen, and they often appress the flexed hindleg close against the ground.

After basking, the adults begin to walk and fly about the habitat. The males are more active than the females, perhaps searching for receptive females with which to mate. Females walk and fly far less than males, but do more feeding, grooming, and resting.

In the afternoon the adults bask on bare ground for a second time beginning about 3 p.m. and ending about 5 p.m. Then they walk or fly to vegetated areas where they seek shelter usually under canopies of grasses.

Habitat

Found often along roadsides, nearly bare ground.

Reproduction

Hatching
The Carolina grasshopper is an intermediate-hatching species. In eastern Wyoming hatching may start in early June or may be delayed until late June. Although egg development has not been studied in this species, the fact that oviposition takes place late in summer suggests that much development probably occurs during the following spring. This speculation appears more plausible in view of the results of subjecting overwintered field-collected eggs to five different constant temperatures. At 77°F, eggs of the Carolina grasshopper completed incubation in 22 days, whereas the twostriped grasshopper Melanoplus bivittatus completed incubation in 7 days and the differential grasshopper, M. differentialis in 21 days. Egg development of the Carolina grasshopper appears more like that of the differential grasshopper, which achieves less growth before diapausing than the twostriped.

Nymphal Development
The nymphs emerge over a period of at least two weeks and develop in a habitat of grass and weeds with much interspersed bare ground. Hatching, however, may at certain times and places be extended over several weeks so that as many as four different instars (I to IV) coexist together in a habitat. Limited data obtained in eastern Wyoming indicate a nymphal period of 40 days at an altitude of 4,700 feet and 55 days at an altitude of 6,100 feet. Reared in the laboratory, nymphs complete development in 52 days at a constant temperature of 77°F and 26 days at a constant temperature of 86°F. The Carolina grasshopper has been described as a heat-loving species that prefers the hot, bare areas of its habitat.

Adults and Reproduction
The adults appear during May in New Mexico and eastern Nebraska, during early July in eastern Wyoming, and during late July in western Idaho. Once Carolina grasshoppers acquire functional wings, they fly and disperse extensively. Adults may move distances of several miles or more, as they have been found in the center of large cities. The full extent of individual dispersal, however, is unknown.

The habitat in which the eggs hatched and the nymphs developed remains occupied by adults, most likely by an assemblage composed of some of the original inhabitants and some immigrants. The males court females by producing a calling signal using their hindlegs and wings to stridulate. One hindleg at a time is rubbed against the tegmen in a behavior called alternate stridulation. A male sits horizontally on bare ground in sunlight and may continue to call for 5 minutes or longer until he attracts a female. She walks toward him and when she is close he approaches her and mounts. If he is successful, the pair mate. They may remain in copulo for as long as 16 hours.

Sexual maturation of females appears to be prolonged. In Minnesota, where the adult stage is reached in early June, the females do not begin to oviposit until early August, suggesting that nine weeks are required for maturation. In Manitoba, oviposition has been observed in September and in Wyoming in September and October.

The female selects compact bare ground exposed to the sun in which to oviposit. The selected site is often the edge of a gravel or dirt road. She works her ovipositor to a depth of 1 1/2 inches and deposits a large clutch of eggs that she encloses in a sharply curved pod. After approximately 1 1/3 hours, she extracts her ovipositor and for one to three minutes brushes surface particles with her hind tarsi over the aperture of the hole. The pod, nearly 2 inches long, usually contains more than 40 eggs. Two egg pods obtained after observing the females oviposit at the edge of a gravel road in southeastern Wyoming contained 50 and 57 eggs, respectively. Reared in a greenhouse, caged females have laid from 30 to as many as 70 eggs in a pod. The eggs are reddish brown and 4.8 to 5.8 mm long.

Food

Grasses, forbs, horsetails (Equisetum).

Cultural

The Carolina grasshopper is a minor pest of rangeland grasses. Populations occur chiefly in disturbed areas where it feeds mainly on several species of weeds. The populations that irrupt in favorable habitats, however, may disperse and damage crops. Disturbed areas reseeded with smooth brome foster large numbers of this species, which not only feed on the brome but often fly to fields of fall wheat where they cause stand damage. An outbreak of the Carolina grasshopper that irrupted in southern Saskatchewan in 1933 and 1934 caused considerable damage to the crops of this region. In some years the species has damaged tobacco in southern Ontario. It has also been recorded as causing minor damage to alfalfa. In 1935 it was especially destructive to field beans in the vicinity of Flagstaff, Arizona. In Oklahoma it has been reported to damage corn, sorghum, cotton, and potato. No detailed study of its economic importance, however, has been made.