Beetles are 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 described 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, with estimates suggesting that there are between 0.9 to 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.
Spercheus is a genus of aquatic beetles which are placed in a family of their own, Spercheidae. About 20 species are known from around the world, with the majority being from the Oriental and Afrotropical Realms.
The whirligig beetles are a family (Gyrinidae) of adephagan 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.
The Hydroscaphidae are a small family of water beetles known commonly as skiff beetles. As of 2010, there are 23 species in the family. Several are recently described.
Rhysodidae is a family of beetles, consisting of more than 350 species in about 20 genera.
The Haliplidae are a family of water beetles that swim using an alternating motion of the legs. They are therefore clumsy in water, and prefer to get around by crawling. The family consists of about 200 species in 5 genera, distributed wherever there is freshwater habitat; it is the only extant member of superfamily Haliploidea. They are also known as crawling water beetles or haliplids.
The Adephaga, 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 collectively known as adephagans. The largest family is Carabidae which comprises most of the suborder with over 40,000 species. Adephaga also includes a variety of aquatic beetles, such as predaceous diving beetles and whirligig beetles.
Histeroidea is a superfamily of beetles in the infraorder Staphyliniformia.
Helophorus ís the only genus in the beetle family Helophoridae. They are small insects, found mainly in the Holarctic region, but two or three species also live in the Afrotropical region, Central America and one in the Indomalayan region.
Hygrobia is a genus of aquatic beetles native to Europe, North Africa, China and Australia. It is the only genus in the family Hygrobiidae, also known as the Paelobiidae. These are known commonly as squeak beetles or screech-beetles.
Acilius sulcatus is a species of water beetle in family Dytiscidae.It is fairly large, with color variation shown throughout its range. Typically it is yellow and black.
Coptoclavidae is an extinct family of aquatic beetles in the suborder Adephaga. The Coptoclavidae lived from the Late Triassic to the Early Cretaceous. Coptoclavidae is a member of the adephagan clade Dytiscoidea., which contains other aquatic beetles. Suggested reasons for their extinction to include the rise of teleost fish, or competition with Gyrinidae and Dytiscidae, which possess defensive secretions and sucking channels in the mandibles of larvae, which coptoclavids likely lacked. It has been suggested that the genus Timarchopsis and the subfamily Timarchopsinae are only distantly related to other coptoclavids based on cladistic analysis, with Timarchopsis being more closely related to geadephagans like carabids and trachypachids instead. Another study also suggested similarly for Coptoclavisca and possibly other coptoclaviscines.
Amphizoa insolens is a species of aquatic beetles. It is found in North America from Alaska to southern California.
Pactolinus gigas is a species of the Histeridae family of Beetles.
Aspidytes is a genus of aquatic beetles in the family Aspidytidae, first recorded in 2002 from specimens in South Africa. Originally a second species from China was placed in the same genus but has later been transferred to Sinaspidytes. The genus contains the single species Aspidytes niobe. The aquatic beetle is 6.5 - 7.2 mm long and lives in hygropetric habitats.
Oreodytes scitulus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.
Amphizoa striata is a species of trout-stream beetle in the family Amphizoidae. It is found in North America. It is between 13 and 15 millimeters long. Its front tarsi have a well-developed groove on the posterior surface and grooves bearing a fringe of long hair-like setae. It lives in British Columbia, Oregon, and Washington.
Oxynopterus mucronatus, sometimes known as the giant click beetle, is a species of click beetle from tropical Southeast Asia. Their larvae are specialized predators of termites.
Aspidytidae is a family of aquatic beetles of the suborder Adephaga, described in 2002 from specimens in South Africa and China. There are only two known species in the family and these were originally described in the genus Aspidytes, but later the new genus Sinaspidytes was erected for the species found in China. The family can also be referred to by its trivial name cliff water beetles.
Sinaspidytes is a genus of aquatic beetles in Aspidytidae, first recorded in 2003 from specimens in the Shaanxi province, China. It is monotypic, with the only species being Sinaspidytes wrasei. Originally this species was placed in the genus Aspidytes with a second species from South Africa, but was later transferred to Sinaspidytes. The genus contains the single species S. wrasei. The aquatic beetle is 4.8 - 5.2 mm long and lives in hygropetric habitats.
