Sand Worms Clam Worms and Tubeworms: Polychaeta

Physical characteristics: Honeycomb worm adults measure 1.1 to
1.5 inches (30 to 40 millimeters) long. The body trunk has three pairs of flattened bristles that form a cover to close the tube opening. The colors of the tubes are determined by the sand and other materials used to construct them.

Geographic range: Honeycomb worms are found in the Mediterranean Sea and north Atlantic to south Morocco. They are also found in the British Isles to its northern limit in the northeast Atlantic.

Habitat: Honeycomb worms are found along open coasts. They need hard surfaces to attach their tubes, but require sand and shell fragments to make their tubes.

The reefs created by honeycomb worm tubes help to create habitats for other marine species. (Illustration by Amanda Humphrey. Reproduced by permission.)

Diet: They eat seston (SEHS-tun), bits of plant and animal materials that float by in the water during high tide.

Behavior and reproduction: The honeycomb worm lives in dense colonies and builds tubes that are permanently attached to hard surfaces. The tubes are made using coarse sand and/or bits of shells. The openings to the tubes are so tightly packed together they resemble a honeycomb. The tubes are up to 7.8 inches (20 centimeters) in length, with openings up to 0.19 inches (5 millimeters) in diameter. If the tubes are exposed during low tide, the worms will survive by plugging the entrance with a cover to avoid drying out or being eaten by other animals.

Males and females reproduce every year. The female produces from one hundred thousand to one million eggs at a time. The larvae eat plankton, or microscopic plants and animals drifting in water. Larvae may drift up to 6.2 miles (10 kilometers) from where they hatched.

Honeycomb worms and people: The reefs created by honeycomb worm tubes help to create habitats for other marine species. Fishermen collect and use honeycomb worms as bait.

Conservation status: The honeycomb worm is not considered endangered or threatened. ∎