''Asellus aquaticus'' is a

freshwater 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 ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

resembling a

woodlouse A woodlouse (plural woodlice) is an isopod crustacean from the polyphyleticThe current consensus is that Oniscidea is actually triphyletic suborder Oniscidea within the order Isopoda. They get their name from often being found in old wood. ...

. It is known by various common names including pond slater, water louse, aquatic sowbug, water hoglouse and cress bug.

Ecology

''Asellus aquaticus'' is common throughout the

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

zone including

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

, and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. It is found in

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a stream ...

s and

standing water Water stagnation occurs when water stops flowing. Stagnant water can be a major environmental hazard. Dangers Malaria and dengue are among the main dangers of stagnant water, which can become a breeding ground for the mosquitoes that transmi ...

, particularly where there are plenty of stones under which it hides, but it is not found where the water is strongly acidic. It is a

detritivore Detritivores (also known as detrivores, detritophages, detritus feeders, or detritus eaters) are heterotrophs that obtain nutrients by consuming detritus (decomposing plant and animal parts as well as feces). There are many kinds of invertebrates, ...

. ''Asellus aquaticus'' is relatively tolerant of a range of

pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...

s and has been used as an indicator of

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

Life cycle and reproduction

''Asellus aquaticus'' can breed throughout the year, if the temperature is high enough: they do not breed under cold temperatures. Maturity can be reached in few months under warm summer temperatures, but maturation may take as much as two years in permanently cold water bodies (e.g., high-latitude or mountain waters). Life span varies similarly: from 9 months in South Africa to 20 months in Northern Europe. Females carry eggs in brood pouches underneath their body.

Aquarium keeping

Aquarists worldwide are showing increasing interest towards ''A. aquaticus'' as a low-maintenance freshwater aquarium pet and tank cleaner. While often sold as live food for other fish, some keepers in the US and Germany have started selectively breeding ''A. aquaticus'' to be sold as pets, usually from online platforms like eBay.

Conservation

A number of

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

are considered to be

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

including: *''Asellus aquaticus carniolicus'',

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to Slovenia. *''Asellus aquaticus cavernicolus'' found only in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

and

Slovenia Slovenia ( ; sl, Slovenija ), officially the Republic of Slovenia (Slovene: , abbr.: ''RS''), is a country in Central Europe. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, an ...

. *''Asellus aquaticus cyclobranchialis'', endemic to Slovenia.

References

{{Taxonbar, from=Q586336 Asellota Freshwater crustaceans of Europe Freshwater crustaceans of Asia Freshwater crustaceans of North America Crustaceans described in 1758 Taxa named by Carl Linnaeus Taxobox binomials not recognized by IUCN