Orthoptera

“I’ve learnt to gather simplicity from grasshoppers. I like their naive indecisive minds never knowing exactly when to stop chirping, and I envy their ability to be able to mingle with the green…” – Munia Khan.

The Orthoptera are the order of insects that contain the grasshoppers, crickets and katydids (aka bush crickets), and have about 20,000 species. These insects are characterized by having incomplete metamorphosis, elongated legs for jumping and a pronotum that extends down the abdomen. Orthopterans can produce sound, used for mating, by rubbing their wings together or on their legs, which is known as stridulation. Grasshoppers are able to fold their wings, so are palced in the group Neoptera.

IMPORTANCE. Locust are important pests of agricultural crops in places like Australia, as when they are in their gregarious phase (for migration), they form these marching bands or swarms that strip the foliage from any crop they come across. Timings and locations of migrations of the desert locust (Schistocerca gregaria) is difficult to predict and controlling their populations is a huge challenge. Several grasshoppers species in the UK are of conservation interest, including the heath grasshopper, wart-biter cricket and mole cricket.

CLASSIFICATION. Orthoptera can be split into 2 suborders, the ensifera (crickets and katydids) and caelifera (grasshoppers). These suborders are further split into families, including the well known acrididae (grasshoppers, locust), gryllidae (true crickets), gryllotalpidae (mole crickets) and tettigoniidae (bush crickets/katydids).

IDENTIFICATION. The ensifera can be identified by presence of very long thread-like multi-segmented antennae, auditory (tympanal) organs on the fore tibiae and usually cryptic colouration. The caelifera are characterized by having an antennae with less than 30 segments, auditory organs at the base of the abdomen and pegs on the hind femur.

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SOUND PRODUCTION. In orthopterans, sound production is used as a mating call and specialized auditory organs have evolved for the purpose, called the tympanal organs (for hearing) and stridulatory structures for production of the sound. In grasshoppers the sound is produced by rubbing of wing against hind femur, and in crickets the wings are rubbed together. Mole crickets will even construct a special cavern underground in order to amplify the sound (see picture).

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