Beetles are insects that form the order Coleoptera, in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 described species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal species; new species are discovered frequently, with estimates suggesting that there are between 0.9 and 2.1 million total species. 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.
The family Scarabaeidae, as currently defined, consists of over 35,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several groups formerly treated as subfamilies have been elevated to family rank, and some reduced to lower ranks. The subfamilies listed in this article are in accordance with those in Catalog of Life (2023).
Stag beetles are a family of about 1,200 species of beetles in the family Lucanidae, currently classified in four subfamilies. Some species grow to over 12 centimetres, but most to about 5 cm (2 in).
Glaresis is a genus of beetles, sometimes called "Enigmatic scarab beetles", in its own family, the Glaresidae. It is closely related to, and was formerly included in, the family Scarabaeidae. Although its members occur in arid and sandy areas worldwide, only the nocturnal adults have ever been collected, and both the larvae and biology of Glaresis are as yet unknown. Due to their narrow habitat associations, a great number of these species occur in extremely limited geographic areas, and are accordingly imperiled by habitat destruction.
Trogidae, sometimes called hide beetles, is a family of beetles with a distinctive warty or bumpy appearance. Found worldwide, the family includes about 300 species contained in four or five genera.
Scarabaeoidea is a superfamily of beetles, the only subgroup of the infraorder Scarabaeiformia. Around 35,000 species are placed in this superfamily and some 200 new species are described each year. Its constituent families are also undergoing revision presently, and the family list below is only preliminary. This superfamily includes some of the largest beetles extant today, including rhinoceros beetles, (Dynastinae), the Hercules beetle and Goliath beetles.
The Hercules beetle is a species of rhinoceros beetle native to the rainforests of southern Mexico, Central America, South America, and the Lesser Antilles. It is the longest extant species of beetle in the world, and is also one of the largest flying insects in the world.
Pleocoma is the only extant genus of rain beetles and is endemic to the Pacific states of North America. Fossil remains of Pleocoma have been found in the Yixian Formation in China, suggesting beetles in this genus have existed in something like their present form since at least the Cretaceous period. There are 27 described species in Pleocoma.
Ripiphoridae is a cosmopolitan family of some 450 described species of beetles sometimes called "wedge-shaped beetles". Ripiphoridae are unusual among beetle families in that many species are hypermetamorphic parasitoids, an attribute that they share with the Meloidae. Members of the family differ in their choice of hosts, but most attack various species of bees or wasps, while some others attack cockroaches or beetles. Many species of Ripiphoridae have abbreviated elytra, and flabellate or pectinate antennae.
The Ommatidae are a family of beetles in the suborder Archostemata. The Ommatidae are considered the extant beetle family that has most ancestral characteristics. There are only seven extant species, confined to Australia and South America. However, the geographical distribution was much wider during the Mesozoic spanning across Eurasia and Australia, suggesting that they were widespread on Pangea. So far, over 26 extinct genera containing over 170 species of these beetles have been described. Three extant genera have been assigned to this family: Omma,Tetraphalerus and Beutelius. The family is considered to be a subfamily of Cupedidae by some authors, but have been found to be more closely related to Micromalthidae in molecular phylogenies. A close relationship with Micromalthidae is supported by several morphological characters, including those of the mandibles and male genitalia. Due to their rarity, their ecology is obscure, it is likely that their larvae feed on deadwood.
Aphodiites is a genus of fossil beetles from the Lias of Schambelen, and the oldest fossil in the superfamily Scarabaeoidea. Its affinities are not apparent; it was initially placed in the Aphodiinae (Scarabaeidae), but its diagnostic characters are shared by beetles such as Glaresis (Glaresidae).
The Brachypsectridae are a family of beetles commonly known as the Texas beetles. There are only two extant genera, Brachypsectra and Asiopsectra. Brachypsectra has a cosmopolitan distribution, mostly in arid regions, while Asiopsectra is found in Central Asia and the Middle East.
Rutelinae or shining leaf chafers is a subfamily of the scarab beetles. It is a very diverse group; distributed over most of the world, it contains some 200 genera with over 4,000 described species in 7 tribes. Several taxa have yet to be described. A few recent classifications include the tribe Hopliini, but this is not generally accepted.
Pleocoma shastensis is a species of rain beetle in the family Pleocomidae. It is found in North America.
Eulichadidae is a family of beetles belonging to Elateriformia. There are two extant genera, Eulichas with several dozen species native to the Indomalayan realm of Asia, and Stenocolus, with a single species native to Western North America. The larvae are aquatic, with the larvae of Eulichas being found in sandy sediments of clean forest streams, while the larvae of Stenocolus are found under rocks and in leaf packs in low elevation streams and rivers. They are herbivious/saprophagous with larval specimens of Eulichas having been found with wood particles in their stomachs, while the larvae of Stenocolus are known to feed on decaying roots and detritus. The adults are terrestrial, with specimens of Eulichas typically found using light, while specimens of Stenocolus are typically found in riparian vegetation, and are not attracted to light. Potential extinct genera have been described from Mesozoic rocks, but the placement of several of these taxa in the family is disputed.
Artematopodidae is a family of soft-bodied plant beetles in the superfamily Elateroidea. They are mostly found in understory forest foliage. The life history of the group is obscure, larvae of the genera Eurypogon and Macropogon likely feed on moss, while the larvae of Artematopus have been fed insect remains. The oldest fossils of the family date to the Middle Jurassic.
Throscidae is a family of elateroid beetles found worldwide with around 150 species in 5 extant genera. The larvae are soil-dwelling, siphoning fluid from mycorrhizae attached to trees. The adults are short-lived, with the adult males being noted for a complex mating dance. Like some other elateroids, they are capable of clicking.
Pleocoma rickseckeri is a species of rain beetle in the family Pleocomidae. It is found in North America. It was named in honor of Lucius Edgar Ricksecker.
Pleocoma hirticollis is a species of rain beetle in the family Pleocomidae. It is found in North America.
Pleocoma rubiginosa is a species of rain beetle in the family Pleocomidae. It is found in North America.
