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 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 whirligig beetles are water beetles, comprising the family Gyrinidae 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. Whirligig beetles belong to the beetle suborder Adephaga, which also includes ground beetles and diving beetles.
A water beetle is a generalized name for any beetle that is adapted to living in water at any point in its life cycle. Most water beetles can only live in fresh water, with a few marine species that live in the intertidal zone or littoral zone. There are approximately 2000 species of true water beetles native to lands throughout the world.
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 are a suborder of beetles, and with more than 40,000 recorded species in 10 families, the second-largest of the four beetle suborders. 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.
The great diving beetle is an aquatic diving beetle native to Europe and northern Asia, and in the UK is common in Wales, much of England and southern Scotland but less common on chalk and in the far north. The great diving beetle, true to its name, is a rather large insect. The larvae can grow up to 60 millimetres (2.4 in) in length, while the adults are generally 27–35 millimetres (1.1–1.4 in).
The Dytiscidae – based on the Greek dytikos (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live among leaf litter. The adults of most are between 1 and 2.5 cm (0.4–1.0 in) long, though much variation is seen between species. The European Dytiscus latissimus and Brazilian Megadytes ducalis are the largest, reaching up to 4.5 cm (1.8 in) and 4.75 cm (1.9 in) respectively. In contrast, the smallest is likely the Australian Limbodessus atypicali of subterranean waters, which only is about 0.9 mm (0.035 in) long. Most are dark brown, blackish, or dark olive in color with golden highlights in some subfamilies. The larvae are commonly known as water tigers due to their voracious appetite. They have short, but sharp mandibles and immediately upon biting, they deliver digestive enzymes into prey to suck their liquefied remains. The family includes more than 4,000 described species in numerous genera.
Dytiscus latissimus is a large species of aquatic beetle in family Dytiscidae. It is native to Europe and considered threatened.
Megadytes is a genus of diving beetles in the family Dytiscidae. They are found in slow-moving or static freshwater habitats throughout most of the Neotropics, ranging from Florida and Mexico, through the West Indies and Central America, to South America as far south as central Argentina. The adult beetles measure about 1.65–4.75 cm (0.6–1.9 in) long depending on the exact species and the largest is also the largest in the family.
Acilius is a holarctic genus of diving beetles in the family Dytiscidae and typically has a life cycle that is univoltine.
Megadytes glaucus is a species of beetles of the family Dytiscidae.
Copelatus marginipennis is a species of diving beetle. It is part of the genus Copelatus in the subfamily Copelatinae of the family Dytiscidae. It was described by Laporte in 1835.
Madaglymbus apicalis is a species of diving beetle. It is part of the genus Madaglymbus in the subfamily Copelatinae of the family Dytiscidae. It was described by Fairmaire in 1898. Madaglymbus apicalis is distributed along the coastlines of much of Africa.
Copelatus haemorrhoidalis is a species of diving beetle. It is part of the genus Copelatus in the subfamily Copelatinae of the family Dytiscidae. It was described by Régimbart in 1883.
Exocelina cheesmanae is a species of diving beetle. It is part of the genus Exocelina in the subfamily Copelatinae of the family Dytiscidae. It was described by J. Balfour-Browne in 1939.
Copelatus taprobanicus is a species of diving beetle endemic to Sri Lanka. It is part of the genus Copelatus in the subfamily Copelatinae of the family Dytiscidae. It was described by Wewalka & Vazirani in 1985.
Madaglymbus unguicularis is a species of diving beetle. It is part of the subfamily Copelatinae of the family Dytiscidae. It was described by Régimbart in 1903.
Copelatinae is a subfamily of diving beetles, in the family Dytiscidae. The subfamily contains seven genera: Agaporomorphus, Aglymbus, Copelatus, Exocelina, Lacconectus, Liopterus, and Madaglymbus. Of these, the largest is Copelatus, which has about 470 described species found worldwide, but most diverse in tropical South America, Africa and South-East Asia.
Megadytes fraternus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America and the Neotropics.
Cybistrini is a tribe of predaceous diving beetles in the family Dytiscidae. There are 7 genera and 128 described extant species in Cybistrini. The same set is also called Cybistrinae by authors viewing is as a subfamily of Dytiscidae.
