daphnia pulex

Daphnia pulex

Daphnia pulex is the most common species of water flea. It has a cosmopolitan distribution: the species is found throughout the Americas, Europe and Australia. It is a model species, and was the first crustacean to have its genome sequenced. Daphnia pulex occurs in a wide range of aquatic habitats, although it is most closely associated with small, shaded pools. Daphnia are prey for a variety of both vertebrate and invertebrate predators. The role of predation on D. pulex population ecology extensively studied, and has been shown to be a major axis of variation in shaping population dynamics and landscape-level distribution.

photo credits: Paul Hebert

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Under The Microscope: Daphnia

Daphnia is a genus of small, planktonic crustaceans, 1–5 millimeters (0.04–0.20 in) in length. Daphnia are members of the order Cladocera, and are one of the several small aquatic crustaceans commonly called water fleas because their saltatory swimming style resembles the movements of fleas. Daphnia live in various aquatic environments ranging from acidic swamps to freshwater lakes, ponds, streams and rivers.

The two most readily available species of Daphnia are D. pulex (small and most common) and D. magna (large). They are often associated with a related genus in the order Cladocera: Moina, which is in the Moinidae family instead of Daphniidae and is much smaller than D. pulex(approximately half the maximum length). Daphnia eggs for sale are generally enclosed in ephippia (a thick shell, consisting of two chitinousplates, that encloses and protects the winter eggs of a cladoceran).

Giffed by: rudescience  From: this video