A water beetle is a generalized name for any

beetle 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 describ ...

that is adapted to living in water at any point in its life cycle. Most water beetles can only live in

fresh water Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

, with a few

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

species that live in the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

littoral zone The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

. There are approximately 2000 species of true water beetles native to lands throughout the world. Many water beetles carry an air bubble, called the elytra cavity, underneath their abdomens, which provides an air supply, and prevents water from getting into the

spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum, a genus of land snails in family Cyclophoridae Cycl ...

s. Others have the surface of their

exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...

modified to form a plastron, or "physical gill", which permits direct gas exchange with the water. Some families of water beetles have fringed hind legs adapted for swimming, but most do not. Most families of water beetles have larvae that are also aquatic; many have aquatic larvae and terrestrial adults.

Diet

Water beetles can be either

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

s, or

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

s. Herbivorous beetles eat only aquatic vegetation, such as

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

or leaves. They might also suck juices out the stem of a plant nearby. Scavenger beetles will feed on decomposing organic material that has been deposited. The scavenged material can come from aquatic vegetation, feces, or other small organisms that have died. The great diving beetle, a predator, feeds on things like worms, tadpoles, and even sometimes small fish.

Species

Families in which all species are aquatic in all life stages include: *

Dytiscidae 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 a ...

Gyrinidae 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 i ...

(Whirligig beetles) *

Haliplidae The Haliplidae are a family of water beetles that swim using an alternating motion of the legs. They are therefore clumsy in water (compared e.g. with the Dytiscidae or Hydrophilidae), and prefer to get around by crawling. The family consists o ...

Noteridae Noteridae is a family of adephagan water beetles closely related to the Dytiscidae, and formerly classified with them. They are mainly distinguished by the presence of a distinctive "noterid platform" underneath, in the form of a plate between t ...

Amphizoidae ''Amphizoa'' is a genus of aquatic beetles in the suborder Adephaga, placed in its own monogeneric family, Amphizoidae.Hygrobiidae ''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.Nilsson, A. N. (2006)Which name is valid – Hygrobiidae or Paelobiidae ...

(Squeak beetles) * Meruidae *

Hydroscaphidae 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. These beetles are small, most under in length. They are tan to brown in colo ...

(Skiff beetles). Families in which the adults are not necessarily aquatic include: *

Hydrophilidae 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 ...

Lutrochidae Lutrochidae is a family of water beetles with a single genus ''Lutrochus'' sometimes known as "travertine beetles". There are around 21 species native to the Americas from the southern United States to Brazil. They are distinguished by their ov ...

(Travertine beetles) *

Dryopidae Dryopidae is a family of beetles, commonly named long-toed water beetles, in the superfamily Byrrhoidea. It was described by Gustaf Johan Billberg in 1820. Description Long-toed water beetles are named for their extended claws. Adults have dens ...

Elmidae Elmidae, commonly known as riffle beetles, is a family (biology), family of beetles in the superfamily Byrrhoidea described by John Curtis (entomologist), John Curtis in 1830. Both adults and larvae are usually aquatic, living under rocks in fas ...

Eulichadidae 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 Ameri ...

Heteroceridae Heteroceridae, the variegated mud-loving beetles, are a widespread and relatively common family of beetles found on every continent except for Antarctica. Around two hundred and fifty species of heterocerids are known to occur worldwide. They a ...

Limnichidae Limnichidae, commonly called minute marsh-loving beetles, is a family of beetles belonging to Byrrhoidea. There are at least 30 genera and 350 described species in Limnichidae. They are found worldwide, with the greatest diversity in tropical regi ...

Psephenidae Water-penny beetles are a family (the Psephenidae) of 272 species (in 35 genera) of aquatic beetles found on all continents except Antarctica, in both tropical and temperate areas. The young, which live in water, resemble tiny pennies. The larv ...

(Water-penny beetles) *

Ptilodactylidae Ptilodactylidae is a family of beetles belonging to the Elateriformia. There around 500 extant species in 35 genera. They are generally associated with riparian and aquatic habitats. The larvae generally live associated with rotting wood or veg ...

Torridincolidae The Torridincolidae are a small family of beetles in the suborder Myxophaga. It contains these genera:Sphaeriusidae ''Sphaerius'' is a genus of beetles, comprising 23 species, which are the only living members of the family Sphaeriusidae. They are typically found along the edges of streams and rivers, where they feed on algae; they occur on all continents ex ...

References

Epler, J. H. 1996. Identification manual for the water beetles of Florida (Coleoptera: Dryopidae, Dytiscidae, Elmidae, Gyrinidae, Haliplidae, Hydraenidae, Hydrophilidae, Noteridae, Psephenidae, Ptilodactylidae, Scirtidae). (PDF, 9.0 MB)
{{DEFAULTSORT:Water Beetle Beetles by adaptation Aquatic insects Insect common names

Diet

Species

See also

References