Ragworm

Hediste diversicolor

ORDER

Phyllodocida

FAMILY

Nereididae

TAXONOMY

Nereis diversicolor (Müller, 1775), Baltic Sea.

OTHER COMMON NAMES

English: Bristleworm, clamworm.

PHYSICAL CHARACTERISTICS

Body elongated and flattened with conspicuous parapodia with bristles. The head has four eyes, two antennae, and two palps. Has eversible pharynx; armed with chitinous teeth. Color is greenish during spawning season and varies from red to light brown at other times.

DISTRIBUTION

Widely distributed throughout northwest Europe in the Baltic Sea, North Sea, and along Atlantic coast to the Mediterranean.

HABITAT

Euryhaline. Found in sandy and muddy sheltered environments in intertidal region.

BEHAVIOR

Solitary organism that builds conspicuous burrow that serves as a site for foraging and as refuge against predation by birds.

FEEDING ECOLOGY AND DIET

Has great variety of feeding modes: passive suspension feeder; surface and subsurface deposit feeder; active and passive omnivore; and scavenger preying on small invertebrates, plant material, or ingesting sand and mud particles to utilize the attached detritus. Utilizes eversible pharynx to capture prey.

REPRODUCTIVE BIOLOGY

Gonochoristic, oviparous, reproducing once in entire life. Larva is lecithotrophic. Maturation and spawning influenced by temperature in spring, and during this phase, males are brighter green and females are darker green. Reproductive pheromones coordinate processes such as mate location and synchronism for release of gametes when males discharge sperm around burrow of females. Adults reach maturity in one to three years.

CONSERVATION STATUS

Not listed by the IUCN.

SIGNIFICANCE TO HUMANS

Important food source for different species of wading birds and serves as bait for fishermen.