Clitellate annelids · Lumbriculida · Lumbriculidae

Aquatic Oligochaete Worm

Lumbriculus variegatus

Not Evaluated

It has not yet been assessed against the IUCN criteria. See full glossary

The California blackworm is an oligochaete that lives in North America and Europe. It lives in shallow-water marshes, ponds and swamps, feeding on microorganisms and organic material. An adult has roughly between 150 and 250 segments, each of which is able to regenerate into a new individual when separated from the rest of the animal.

Size

4 cm – 10 cm

Diet

Omnivore

Combines animal and plant food depending on availability.

Social structure

Colony

Lives in large concentrations, often for breeding reasons.

Sighting difficulty

Unknown

FreshwaterOmnivore Colonial Freshwater Worm

63countries

Fun facts

It reproduces by breaking into pieces: each fragment regrows a new head and tail and becomes a complete individual within a few weeks.
It is a reference organism in ecotoxicology, and standardised sediment toxicity tests are largely carried out with it.
It is bred on a large scale as live food for aquarium fish, where it is known as the California blackworm.
It reproduces almost entirely by fragmentation: it breaks into pieces and each one regrows a head and a tail within days. Almost all populations are clones.
It has two giant neurons running the length of its body that control two different escape responses: touch the head and it pulls back, touch the tail and it shoots forward. That simplicity has made it a standard model in neurophysiology teaching.
It breathes through its tail, which it sticks out of the sediment and waves to renew the water; the less oxygen there is, the more it waves.
It is a standard organism in sediment ecotoxicology: freshwater bioaccumulation tests are run on it.
It is mass-reared as live food for aquarium fish, where it is known as blackworm.