Female Daphnia longispina carrying a resting egg (

''Daphnia longispina'' is a planktonic

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 ...

of the family

Daphniidae Daphniidae is a family of water fleas in the order Anomopoda. Description Members of the family Daphniidae differ from other, similar diplostracans, such as the Macrotrichidae and Moinidae, in that the antennae of females are short and immobile ...

, a

cladocera The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more ...

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 ...

water flea The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more ...

. It is native to

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago a ...

. ''D. longispina'' is similar in size and sometimes confused with the often sympatric '' D. pulex'' (a very common species), but much smaller than '' D. magna''. ''D. longispina'' is found in a wide range of standing freshwater bodies from small, ephemeral rock-pools to large lakes.

Life history

Like all ''Daphnia'' species, ''D. longispina'' is a filter feeder, collecting particles of about 2 to 40 µm suspended in the water. The main food are green algae. At 20 °C maturity is reached within about 6 to 12 days, followed by a period of regular reproduction in about 3-4 day intervals. ''D. longispina'' reproduces either asexually (''

parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development ...

'') or sexually. For the later, females need to produce sons asexually. The same or other females can switch at any moment from asexual to sexual reproduction, but producing haploid eggs, which require fertilization by males. The sexual eggs are then deposited in an ephippium (plural: ''

ephippia Ephippia (singular: ephippium) are winter or dry-season eggs of the various species of small crustacean in the order Cladocera (within the Branchiopoda); they are provided with an extra shell layer, which preserves and protects the resting ...

'', a resting egg shell), which will sink into the bottom of the water body when the female molts her carapace. After a resting period, which can last several years, the resting stages hatches. Only females emerge from the resting stages.

Systematics and evolution

Within the genus ''Daphnia'', ''D. longispina'' belongs to the subgenus ''Hyalodaphnia'', sometimes called the ''D. longispina'' complex. Closely related species of ''D. longispina'' in this complex are '' D. galeata'' and '' D. cucullata'', with which ''D. longispina'' frequently hybridises. A revision of the species complex recently showed that the species ''D. rosea'', ''D. hyalina'' and ''D. zschokkei'' belong to the species ''D. longispina'', invalidating their species status.

Parasitism

In contrast to other ''Daphnia'' species, (e.g. ''D. magna'') only few parasites have been reported to infect ''D. longispina''. It is however frequently subject to colonization by epibionts, such as peritrich ciliates and algae

References

General references

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External links

{{Taxonbar, from=Q4576630 Cladocera Freshwater crustaceans of Europe Crustaceans described in 1776 Taxa named by Otto Friedrich Müller