The Differences Between Locusts, Grasshoppers & Cicadas

Locust vs. Grasshoppers and Cicadas

• A locust is a grasshopper that has joined a swarm and -- through the release of serotonin -- begins to behave very much like a hive insect. Locusts tend to be in the family acrididae, like the rainbow grasshopper or the large -- 38 to 64 millimeter (mm) -- horse lubber. A swarm of locusts forms when there is an explosion in population, an abundance of food and the right weather conditions, including rainfall and temperature. Swarms of locusts can do terrible damage to crops. The Magicicada, or 17-year cicada, emerges from the nymph stage in large broods. Although they don't damage crops like locusts, crowds of flying, singing cicadas can be a nuisance. Female cicadas cutting slits in twigs to lay their eggs can also damage young trees.

Morphology

• Cicadas are much more robust than grasshoppers. The 17-year variety have black bodies, clear wings, red eyes and wing veins. Dog day cicadas are green with clear wings. Both types have wings that extend noticeably past their bodies. Grasshopper's wings are shorter relative to their body length. The hind legs of grasshoppers and locusts are adapted for jumping and they have a more slender body silhouette than a cicada. They come in many colors, from leaf green to brown to multi colored to mottled brown and gray.

Behavior

• Grasshopper, locust and cicada males sing to attract females, but cicadas have a variety of songs and calls, including alarm calls and at least three courtship songs. Grasshoppers sing by rubbing one wing against the other or rubbing their wings against their legs. Cicada males sing by way of tymbals on the sides of their abdomen.

Reproduction

• The cicada has a fascinating and much-studied reproductive cycle. The female makes a slit in the twig of a tree with her ovipositor and lays her eggs. When the cicada nymphs hatch, they fall to the earth and burrow 6 to 18 inches underground. In the case of Magicicada septendecim, the nymphs stay underground for 13 to 17 years and go through several molts. The nymph of the dog day cicada only remains underground for two years, feeding on juices from the roots of deciduous trees. When mature, the cicada nymph makes an exit tunnel, crawls up the bark of a tree or plant and endures one final molt to become an adult. In contrast, grasshoppers usually lay their eggs in the soil. The nymphs emerge in the spring and -- following a series of molts -- become adults.