Arthropods • Earth.com

Mormon cricket

(Anabrus simplex)

galery

Description

The Mormon cricket (Anabrus simplex) is a large insect that can grow to almost 8 cm (3 inches) in length. It lives throughout western North America in rangelands dominated by sagebrush and forbs. Despite its name, the Mormon cricket is actually a shieldbacked katydid, not a cricket. It takes its name from Mormon settlers in Utah, who encountered them while pushing westward, and for the prominent role they play in the miracle of the gulls. Although flightless, the Mormon cricket is capable of traveling up to two kilometers a day in its swarming phase, during which it is a serious agricultural pest and traffic hazard. Mormon crickets have variable coloration. The overall color may be black, brown, red, purple or green. The "shield" (pronotum or modified prothorax that covers vestigial wings) behind the head may have colored markings. The abdomen may appear to be striped. Females have a long ovipositor, which should not be mistaken for a stinger. Both sexes have long antennae. Mormon crickets may undergo morphological changes triggered by high population densities, similar to those seen in locusts. The most noticeable change is in coloration: solitary individuals typically have green or purple coloration, while swarming individuals are often black, brown or red. Mormon cricket eggs hatch mostly in the spring after they are laid, although in some areas eggs may take as many as five years to hatch. Hatching begins when soil temperatures reach 4 °C (40 °F). The nymphs pass through seven instars before reaching the adult stage, typically taking 60 to 90 days. Breeding begins within 10 to 14 days of reaching the adult stage. The male passes to the female a large spermatophore which can be up to 27% of his body weight. The spermatophore is mostly food for the female to consume but also contains sperm to fertilize her eggs. This nuptial gift causes swarming-phase females to compete for males, a behavior not seen in solitary-phase females. The female lays her eggs by thrusting her ovipositor deep into the soil. Each female can lay over one hundred eggs, with individual eggs having the appearance of a grain of rice with a gray to purplish color. The Mormon cricket exists in populations of relatively low density throughout most of its range. At certain times and places, however, population explosions or infestations occur in which large numbers of the crickets form roving bands.

Taxonomic tree:

Domain:
Kingdom: Animalia
Phylum:
Class: Insecta
Order:Orthoptera
Family:Tettigoniidae
Genus:Anabrus
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