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.
Spercheus is a genus of aquatic beetles which are placed in a family of their own, Spercheidae within the Hydrophiloidea. About 20 species are known from around the world except the Nearctic with the majority being from the Oriental and Afrotropical Realms.
Darkling beetle is the common name for members of the beetle family Tenebrionidae, comprising over 20,000 species in a cosmopolitan distribution.
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 the eastern Palearctic. They are sometimes referred to by the common name troutstream beetles.
Hydrophilidae, also known colloquially as water scavenger beetles, is a family of beetles. Aquatic hydrophilids are notable for their long maxillary palps, which are longer than their antennae. Several of the former subfamilies of Hydrophilidae have recently been removed and elevated to family rank; Epimetopidae, Georissidae, Helophoridae, Hydrochidae, and Spercheidae. While the majority of hydrophilids are aquatic, around a third of described species are terrestrial, mostly belonging to the subfamily Sphaeridiinae.
Staphyliniformia is a large infraorder of beetles. It contains over 70,000 described species from all regions of the world. Most species occur in moist habitats - various kinds of rotting plant debris, fungi, dung, carrion, many live in fresh water.
Pselaphinae are a subfamily of beetles in the family Staphylinidae, the rove beetles. The group was originally regarded as a separate family named Pselaphidae. Newton and Thayer (1995) placed them in the Omaliine group of the family Staphylinidae based on shared morphological characters.
The Eumolpinae are a subfamily of the leaf beetles, or Chrysomelidae. It is one of the largest subfamilies of leaf beetles, including more than 500 genera and 7000 species. They are oval, and convex in form, and measure up to 10 mm in size. Typical coloration for this subfamily of beetles ranges from bright yellow to dark red. Many species are iridescent or brilliantly metallic blue or green in appearance.
The Cassidinae are a subfamily of the leaf beetles, or Chrysomelidae. The antennae arise close to each other and some members have the pronotal and elytral edges extended to the side and covering the legs so as to give them the common name of tortoise beetles. Some members, such as in the tribe Hispini, are notable for the spiny outgrowths to the pronotum and elytra.
Histeroidea is a superfamily of beetles in the infraorder Staphyliniformia.
Helophorus ís the only genus in the beetle family Helophoridae within the Hydrophiloidea. 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.
Hydrochus is the only living genus of beetle in the family Hydrochidae, which belongs to the superfamily Hydrophiloidea, and was formerly treated as a subfamily of Hydrophilidae. Hydrochus includes about 180 species, which are found worldwide. The name "Hydrochus" has also been used for a fly genus in the family Dolichopodidae, but this is a junior subjective synonym of the genus Rhaphium.
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.
Margarinotus is a genus of clown beetles in the family Histeridae. There are at least 110 described species in Margarinotus.
Tarsostenus is a genus of checkered beetles in the family Cleridae. It includes the cosmopolitan species T. univittatus.
Psammophory is a method by which certain plants armor themselves with sand on their body parts, lowering the chance of them being eaten by animals. Over 200 species of plants hailing from 88 genera in 34 families have been identified as psammorphorous.
Horelophus walkeri is a small water scavenger beetle that is endemic to New Zealand. It is found in the South Island in the West Coast, Nelson, Buller and Marlborough regions. The preferred habitat of this species are the moss and crevices within the splash zone of waterfalls sourced from fast flowing, clear, cool waterways. The larvae of this species are carnivorous while the adults are herbivores or scavengers. In 2012 the Department of Conservation classified this beetle as Nationally Endangered.
Epimetopidae is a family of semi-aquatic beetles belonging to the Hydrophiloidea. They are found in sand and gravel at the edges of streams, rivers and shallow freshwater ponds. These beetles are shorter than half a centimeter long and have a pronotum with a central projection forming a shelf above the head. On the underside of the abdomen only four sternites are visible. There are approximately 72 described species in three genera, Epimetopus which is restricted to the New World, mostly Neotropical, Eupotemus with two Afrotropical species and Eumetopus with some Oriental species. Females carry their eggcases on the underside of the abdomen. The larvae are probably carnivorous based on their mouthparts and likely live in the same habitats as the adults.
Acidocerus aphodioides is a species of water scavenger beetle in the family Hydrophilidae. It is the only species in the genus Acidocerus. It is known only from Mozambique.
Helopeltarium is a genus of water scavenger beetle in the family Hydrophilidae represented by only one species. It is known only from Myanmar.
