click beetle

 

common name for members of the widespread beetle family Elateridae. Also called elater beetle, the click beetle has a hinge across the front of the body that allows it to flex, and a spine-and-groove arrangement on the underside of the body that provides a snapping mechanism. When a click beetle is turned on its back it cannot right itself by rolling onto its short legs. It arches its body upward so that only the ends touch the ground, then straightens suddenly, causing the spine to slide into the groove. This sends the beetle spinning through the air and produces a loud click. If the beetle lands on its back again it repeats the performance. A click beetle also snaps its body when it is picked up, which may cause the predator to drop it. Click beetles have long, flat bodies, generally rectangular, but curved at the ends. They range in length from ¹/₄ in. to 4 in. (6.4–102 mm); most are black or brown. Most adults are nocturnal leaf-eaters. The larvae, called wireworms, are destructive to a large variety of plants. Some tropical click beetles are brilliantly luminescent. Click beetles are classified in the phylum Arthropoda, class Insecta, order Coleoptera, family Elateridae.

Click beetles
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Superfamily: Elateroidea Family: Elateridae Leach, 1815
Genera
Many: see text

Click beetles (family Elateridae), sometimes called elaters, skipjacks, snapping beetles, or spring beetles, are a cosmopolitan family characterized by the unusual click mechanism they possess. There are a few closely-related families in which a few members have the same mechanism, but all elaterids can click. A spine on the prosternum can be snapped into a corresponding notch on the mesosternum, producing a violent "click" which can bounce the beetle into the air. Clicking is mainly used to avoid predation, although it is also useful when the beetle is on its back and needs to right itself. There are about 7000 known species.

Click beetles can be large and colorful(some are brilliant metallic green), but most are small to medium-sized (<2 cm) and dull. The adults are typically nocturnal and phytophagous. In hot weather, they are prone to enter people's houses at night if entries or windows are left opened. The larvae of a few species, called wireworms, can be serious pests of corn and other grains, especially after a field has been left fallow.

Wireworms are slender, elongate, cylindrical or somewhat flattened, and relatively hard-shelled for larvae. The three pairs of legs on the thoracic segments are short and the last abdominal segment is, as is frequently the case in beetle grubs, directed downwards to serve as a terminal proleg. The posterior end of the body is acutely pointed in the larvae of the species of Agriotes that are the best known of the wireworms, but in another common form (the grub of Athous haemorrhoidalis) the tail is bifid and beset with sharp processes. They may pass a long life (two or three years) in the soil, feeding on the roots of plants, and they often cause much damage to farm crops of all kinds, but especially to cereals. The subterranean habits of wireworms make it hard to exterminate them when they have once begun to attack a crop, and the most hopeful practice is, by rotation and by proper treatment of the land, to clear it of the insects before sowing. Passing easily through the soil on account of their shape, wireworms travel from plant to plant, and thus injure the roots of a large number in a short time. Other subterranean creatures such as the leather-jacket grub of crane flies which have no legs, and geophilid centipedes, which may have over two hundred, are often confounded with the six-legged wireworms.

Genera

Actenicerus Adrastus Aeolus Agriotes Agrypnus Alaus Ampedus Anchastus Anostirus Aplotarsus Athous Berninelsonius Betarmon Brachygonus Brachylacon Calambus Cardiophorus Chalcolepidus Cidnopus Conoderus Crepidophorus Ctenicera Dacnitus Dalopius Danosoma Denticollis Diacanthous Dicronychus Dima Drasterius Eanus Ectamenogonus Ectinus Elater Eopenthes Fleutiauxellus Hemicrepidius Horistonotus Hypnoidus

Hypoganus Hypolithus Idolus Ischnodes Itodacne Lacon Limoniscus Limonius Liotrichus Megapenthes Melanotus Melanoxanthus Metanomus Negastrius Neopristilophus Nothodes Oedostethus Orithales Paracardiophorus Paraphotistus Peripontius Pheletes Pityobius Podeonius Porthmidius Procraerus Prodrasterius Prosternon Pseudanostirus Pyrophorus Quasimus Reitterelater Selatosomus Sericus Simodactylus Stenagostus Synaptus Zorochros

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.

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