migratory grasshopper

Migratory grasshopper is a common, medium-sized, spur-throated, short-horned grasshopper. It may be the most common species of grasshopper in North American grasslands. It is common in Minnesota.

Migratory grasshopper is a serious agricultural pest, causing more crop damage than any other species of grasshopper in North America. Nymphs feed on growing seedlings in cultivated fields in the spring. They are a significant threat to wheat, barley, oats, alfalfa, clover, corn, and vegetable crops. When they migrate in massive swarms they may devastate all leafy vegetation wherever they land. Swarms have been detected at all elevations up to 13,000 feet. They have been recorded traveling as much as 575 miles.

Males are 11 ⁄16″ to 15 ⁄16″ long. Females are slightly larger, ¾″ to 1⅛″ long. The overall color is grayish-brown or gray, rarely light green.

The upper plate covering the thorax (pronotum) is flat above, not keeled. It is broadly rounded at the tip (posterior) and does not extend over the abdomen. Below, there is a distinct, spiny bump (spur) on the middle section of the thorax between the bases of the forelegs.

The abdomen is only slightly swollen at the tip. The sensory appendages at the end of the abdomen (cerci) are robust and are rounded at the tip. They are not constricted in the middle or blackened at the tip. The appendages at the base of the supra-anal plate (furcula) on males are widely spread and short, extending less than half way across the supra-anal plate. The plate on the underside of the tip of the abdomen (subgenital plate) is notched.

The wings are long and extend well past the tip of the abdomen when at rest. The front wings (tegmina) are as long or almost as long as the abdomen. They are grayish brown with dark spots and are mostly transparent. The hind wings are clear.

On the head there is a narrow, pale yellow stripe behind each eye the continues onto the pronotum and ends abruptly at the hindmost ridge (principle sulcus). The face is vertical. The compound eye is brown with many pale spots. The antennae are brown toward the tip, pale toward the base, and no more than ½ the length of the body.

On the hind pair of legs, the narrow upper portion (the outer face) of the hind femur is dull yellow and usually banded. The narrow lower portion (the inner face) of the hind femur is sometimes red. The middle portion of the femur (medial area), the broad area between the outer face and inner face, is grooved in a distinct herringbone or chevron pattern. The banding of the outer face is often carried through on the medial area. The fourth segment (tibia) of the hind leg is usually bluish-green or red, but may be brown, yellow, orange, pink, purple, or gray. On all legs the foot (tarsus) is divided into three segments.

Male: 11 ⁄16″ to 15 ⁄16″

Female: ¾″ to 1⅛″

A wide variety of habitats, including prairies, meadows, pastures, abandoned fields, woodland openings, and roadsides.

Early July to late September

As its name implies, the migratory grasshopper congregates into swarms and migrates in search of food.

About six days after mating the female thrusts her ovipositor into the soil at the base of a grass or crop plant and deposits a pod containing 20 to 26 eggs. During the mating season she may mate and lay eggs several times. The eggs hatch in about ten days, depending on the type of the soil, amount of shade, and soil temperature. About 80% of the eggs hatch the year they were deposited. The remaining overwinter and hatch the following year from May to June. After hatching, nymphs undergo five substages of development, shedding their skin each time. They complete the nymphal stage, becoming adults, in 35 to 55 days.

Shoots and other easily digested parts of the same plants that adults feed on.

A wide variety of plants (polyphagous), but especially dandelion, tumble mustard, wild mustard, pepperweed, western ragweed, downy brome, Kentucky bluegrass, barley, and wheat .

Sources

24, 27, 29, 30, 82, 83.

Haarstad, J. 1990. The Acrididae of Minnesota. Final report submitted to the Minnesota Department of Natural Resources. 28 pp.

Hebard, Morgan. (1932). The Orthoptera of Minnesota. University of Minnesota. Minnesota Agricultural Experiment Station. Retrieved from the University of Minnesota Digital Conservancy, https://hdl.handle.net/11299/204015.

Common and widespread

Location: Pennington Co MN