Orthoptera is an order of insects that comprises the grasshoppers, locusts and crickets, including closely related insects such as the katydids and wetas. The order is subdivided into two suborders: Caelifera – grasshoppers, locusts and close relatives; and Ensifera – crickets and close relatives.
More than 20,000 species are distributed worldwide. The insects in the order have incomplete metamorphosis, and produce sound (known as a "stridulation") by rubbing their wings against each other or their legs, the wings or legs containing rows of corrugated bumps. The tympanum or ear is located in the front tibia in crickets, mole crickets, and katydids, and on the first abdominal segment in the grasshoppers and locusts. These organisms use vibrations to locate other individuals.
The name is derived from the Greek ὀρθός orthos meaning "straight" and πτερόν pteron meaning "wing".
Orthopterans have a generally cylindrical body, with elongated hindlegs and musculature adapted for jumping. They have mandibulate mouthparts for biting and chewing and large compound eyes, and may or may not have ocelli, depending on the species. The antennae have multiple joints and filiform type, and are of variable length.
The first and third segments on the thorax are larger, while the second segment is much smaller. They have two pairs of wings, which are held overlapping the abdomen at rest. The forewings, or tegmina, are narrower than the hindwings and hardened at the base, while the hindwing is membranous, with straight veins and numerous cross-veins. At rest, the hindwings are held folded fan-like under the forewings. The final two to three segments of the abdomen are reduced, and have single-segmented cerci. and their wing type is tegmina.
Orthopterans have a paurometabolous lifecycle or incomplete metamorphosis. The use of sound is generally crucial in courtship, and most species have distinct songs. Most grasshoppers lay their eggs in the ground or on vegetation. The eggs hatch and the young nymphs resemble adults, but lack wings and at this stage are often called 'hoppers'. They may often also have a radically different coloration from the adults. Through successive moults, the nymphs develop wings until their final moult into a mature adult with fully developed wings.
The number of moults varies between species; growth is also very variable and may take a few weeks to some months depending on food availability and weather conditions.
Several species of Orthoptera are considered pests of crops and rangelands or seeking warmth in homes by humans. The two species of Orthoptera that cause the most damage are grasshoppers and locusts. Locust are historically known for wiping out fields of crops in a day. Locust have the ability to eat up to their own body weight in a single day. Individuals gather in large groups called swarms, these swarms can range up to 80 million individuals that stretch 460 square miles. Grasshoppers can cause major agricultural damage but not to the documented extent as locust historically have. These insects mainly feed on weeds and grasses, however, during times of drought and high population density they will feed on crops. They are known pest in soybean fields and will likely feed on these crops once preferred food sources have become scarce.
The Orthoptera include the only insects considered kosher in Judaism. The list of dietary laws in the book of Leviticus forbids all flying insects that walk, but makes an exception for certain locusts. Strangely, the dragonfly and cranefly are not kosher, but they are helpless when unable to fly. The Torah states the only kosher flying insects with four walking legs have knees that extend above their feet so that they hop. Thus nonjumping Orthoptera such as mole crickets are certainly not kosher.
With new research showing promise in locating alternative biofuel sources in the gut of insects, grasshoppers are one species of interest. The insect's ability to break down cellulose and lignin without producing greenhouse gases has aroused scientific interest.
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