It builds a characteristic tube which projects from the seabed, consisting of cemented sand grains and shell fragments with a fringe at the top.

[2] L. conchilega lives in a straight tube composed of large sand grains and shell fragments cemented with mucus that protrudes several centimetres from the surface of the sediment.

The long tentacles protrude from the top searching for food particles and are supported by the fringe-like rim of the tube.

Buhr and Winter considered it likely that at low densities, the worm is predominately a detritivore, feeding on organic particles such as foraminiferans, ciliates, copepods, algae and the faeces of echinoderms and molluscs.

[1] At higher densities, it is more likely to be a suspension feeder, feeding on plankton and other organic particles floating in the water column.

[3] Individual mason worms are either male or female and breeding occurs in spring and summer in the northern hemisphere.