A water beetle is a generalized name for any

beetle Beetles are insects that form the Taxonomic rank, 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 40 ...

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 salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include ...

, with a few marine species that live in the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

littoral zone The littoral zone, also called litoral 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 flood ...

. 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 spiracles. Others have the surface of their

exoskeleton An exoskeleton () . is a skeleton that is on the exterior of an animal in the form of hardened integument, which both supports the body's shape and protects the internal organs, in contrast to an internal endoskeleton (e.g. human skeleton, that ...

modified to form a

plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...

, 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 evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s, or

scavenger Scavengers are animals that consume Corpse decomposition, 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 he ...

s. Herbivorous beetles eat only aquatic vegetation, such as

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

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, from the Ancient Greek word δυτικός (''dystikos''), meaning "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 l ...

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 ...

(Whirligig beetles) *

Haliplidae The Haliplidae are a family (biology), 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 f ...

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 (Squeak beetles) *

Meruidae Meruidae is a family of aquatic beetles in the suborder Adephaga, with only one genus and species, ''Meru phyllisae''. The beetle species was first found in the early 1980s.Paul J. Spangler, Warren E. Steiner JR (2005) A new aquatic beetle fami ...

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 col ...

(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 (biology), 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. ...

Elmidae Elmidae, commonly known as riffle beetles, is a family of beetles in the superfamily Byrrhoidea described by John Curtis in 1830. Both adults and larvae are usually aquatic, living under rocks in fast-flowing shallow areas of streams, such as ...

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 Ame ...

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 (biology), family (the Psephenidae) of 273 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 ...

(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 Myxophaga is the second-smallest suborder of the Coleoptera after Archostemata, consisting of roughly 65 species of small to minute beetles in four families. The members of this suborder are aquatic and semiaquatic, and feed on algae. Descriptio ...

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