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Temporal range: Changhsingian/Induan Holocene, 251.2–0  Ma [1]
Dytiscus latissimus.jpg
Dytiscus latissimus , a predaceous diving beetle
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Suborder: Adephaga
Schellenberg, 1806

Extant families:

Meruidae Spangler & Steiner 2005

Extinct families:

Image by Harold Maxwell-Lefroy - Adephaga 76-Indian-Insect-Life - Harold Maxwell-Lefroy - Adephaga.jpg
Image by Harold Maxwell-Lefroy - Adephaga

The Adephaga (from Greek ἀδηφάγος, adephagos, "gluttonous"), with more than 40,000 recorded species in 10 families, are a suborder of highly specialized beetles and the second-largest suborder of the order Coleoptera. Members of this suborder are adephagans, a term which notably include ground beetles, tiger beetles, predacious diving beetles, and whirligig beetles. The majority of the species belongs to the family of carabids, or ground beetles (Carabidae).



Adephagans have simple antennae with no pectination or clubs. The galeae of the maxillae usually consist of two segments. Adult adephagans have visible notopleural sutures. The first visible abdominal sternum is completely separated by the hind coxae, which is one of the most easily recognizable traits of adephagans. Five segments are on each foot.


The transverse fold of the hind wing is near the wing tip. The median nervure ends at this fold, where it is joined by a cross nervure.

Internal organs

Adephagans have four Malpighian tubules. Unlike in other beetles, yolk chambers alternate with egg chambers in the ovarian tubes of adephagans. The coiled, tubular testes consist of a single follicle, and the ovaries are polytrophic.

Chemical glands

All families of adephagan have paired pygidial glands located posterodorsally in the abdomen, which are used for secreting chemicals. The glands consist of complex invaginations of the cuticle lined with epidermal cells contiguous with the integument. The glands have no connection with the rectum and open on the eighth abdominal tergum.

Secretions pass from the secretory lobes, which are aggregations of secretory cells, through a tube to a reservoir lined with muscles. This reservoir then narrows to a tube leading to an opening valve. The secretory lobes differ structurally from one taxon to another; it may be elongated or oval, branched basally or apically, or unbranched.

Delivery of glandular compounds

The secretion is realized in one of these manners:

The secretions differ in the chemical constituents, according to the taxa. Gyrinids, for instance, secrete norsesquiterpenes such as gyrinidal, isogyrinidal, gyrinidione, or gyrinidone. Dytiscids discharge aromatic aldehydes, esters, and acids, especially benzoic acid. Carabids typically produce carboxylic acids, particularly formic acid, methacrylic acid, and tiglic acid, but also aliphatic ketones, saturated esters, phenols, aromatic aldehydes, and quinones. Accessory glands or modified structures are present in some taxa: the Dytiscidae and Hygrobiidae also possess paired prothoracic glands secreting steroids; and the Gyrinidae are unique in the extended shape of the external opening of the pygidial gland.

The function of many compounds remain unknown, yet several hypotheses have been advanced:

Distribution and habitat

Habitats range from caves to rainforest canopy and alpine habitats. The body forms of some are structurally modified for adaptation to habitats: members of the family Gyrinidae live at the air-water interface, rhysodines live in heartwood, and paussine carabids inhabit ant nests.


Most species are predators. Other less-typical forms of feeding include: eating algae (family Haliplidae), seed-feeding (arpaline carabids), fungus-feeding (rhysodine carabids), and snail-feeding (licinine and cychrine carabids). Some species are ectoparasitoids of insects (brachinine and lebiine carabids) or of millipedes (peleciine carabids).

Reproduction and larval stage

Some species are ovoviviparous, such as pseudomorphine carabids.

The larvae are active, with well-chitinized cuticle, often with elongated cerci and five-segmented legs, the foot-segment carrying two claws. Larvae have a fused labrum and no mandibular molae.


Adephagans diverged from their sister group in the Late Permian, the most recent common ancestor of living adephagans probably existing in the early Triassic, around 240 million years ago. Both aquatic and terrestrial representatives of the suborder appear in fossil records of the late Triassic. The Jurassic fauna consisted of trachypachids, carabids, gyrinids, and haliplid-like forms. The familial and tribal diversification of the group spans the Mesozoic, with a few tribes radiating explosively during the Tertiary.

The phylogeny of adephagans is disputed. The group is usually divided into two main groups:

This division is often criticized, as mounting evidence is pointing out that the two groups are not monophyletic.

See also

Related Research Articles

Beetle Order of insects

Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms; new species are discovered frequently. The largest of all families, the Curculionidae (weevils), with some 83,000 member species, belongs to this order. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops.

Ground beetle Family of ground beetles

Ground beetles are a large, cosmopolitan family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it is one of the 10 most speciose animal families.

Whirligig beetle Family of beetles

The whirligig beetles are a family (Gyrinidae) of water beetles that usually swim on the surface of the water if undisturbed, though they swim underwater when threatened. They get their common name from their habit of swimming rapidly in circles when alarmed, and are also notable for their divided eyes which are believed to enable them to see both above and below water. The family includes some 700 extant species worldwide, in 15 genera, plus a few fossil species. Most species are very similar in general appearance, though they vary in size from perhaps 3 mm to 18 mm in length. They tend to be flattened and rounded in cross section, in plain view as seen from above, and in longitudinal section. In fact their shape is a good first approximation to an ellipsoid, with legs and other appendages fitting closely into a streamlined surface.

<i>Amphizoa</i> Genus of beetles

Amphizoa is a genus of aquatic beetles in the suborder Adephaga, placed in its own monogeneric family, Amphizoidae. There are five known species of Amphizoa, three in western North America and two in eastern palearctic. They are sometimes referred to by the common name troutstream beetles.

Apocrine sweat gland mostly limited to the axilla (armpits) and perianal areas in humans; they are not significant for cooling in humans, but are the sole effective sweat glands in hoofed animals, such as the camels, donkeys, horses, and cattle

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Ant nest beetle Subfamily of beetles

Ant nest beetles or paussines, some members of which are known also as flanged bombardier beetles, are a large subfamily within the ground beetles (Carabidae). The tribes Metriini, Ozaenini, Paussini and Protopaussini are included in the subfamily.

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<i>Lebia grandis</i> Species of beetle

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<i>Anchomenus dorsalis</i> Species of beetle

Anchomenus dorsalis is a species of ground beetle in the subfamily Platyninae. It is found in Europe, the Middle East and Central Asia.

<i>Epomis</i> Genus of beetles

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<i>Megadromus antarcticus</i> Species of beetle

Megadromus antarcticus, also known as the “Alexander beetle”, is a member of the Carabidae family and only found in the Canterbury region of New Zealand. Megadromus antarcticus are easily recognized by their iridescent green coloration.


Phagomimicry is a defensive behaviour of sea hares, in which the animal ejects a mixture of chemicals, which mimic food, and overwhelm the senses of their predator, giving the sea hare a chance to escape. The typical defence response of the sea hare to a predator is to release two chemicals - ink from the ink gland and opaline from the opaline gland. While ink creates a dark, diffuse cloud in the water which disrupts the sensory perception of the predator by acting as a smokescreen and as a decoy, the opaline, which affects the senses dealing with feeding, causes the predator to instinctively attack the cloud of chemicals as if it were indeed food. This ink is able to mimic food by having a high concentration of amino acids and other compounds that are normally found in food, and the attack behaviour of the predator allows the sea-hares the opportunity to escape.

Ross Bell American entomologist

Ross Taylor Bell was an American entomologist with particular interest in the invertebrate natural history of Vermont, United States, and carabid beetles. Together with his wife, Joyce Bell, his work at the University of Vermont was largely taxonomic, where they described more than 75% of the rhysodine species known to science. Ross also wrote a number of seminal papers in his chosen field.

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Discoderus parallelus is a ground beetle in the family Carabidae, in the suborder Adephaga . Discoderus parallelus is found in North America.

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<i>Bembidion semicinctum</i> Species of beetle

Bembidion semicinctum is a species of ground beetle in the family Carabidae, in the suborder Adephaga. It was described by American entomologist Howard Notman in 1919.


  1. Wang, Yan-hui; Engel, Michael S.; Rafael, José A.; Wu, Hao-yang; Rédei, Dávid; Xie, Qiang; Wang, Gang; Liu, Xiao-guang; Bu, Wen-jun (2016). "Fossil record of stem groups employed in evaluating the chronogram of insects (Arthropoda: Hexapoda)". Scientific Reports . 6: 38939. doi:10.1038/srep38939. PMC   5154178 . PMID   27958352.