Image Credit: Katja Schulz
Seaweed-flies (Coelopidae) – feeders upon decomposing plants. Along the seacoasts most flowering plants have a very difficult job in attracting potential flower-visiting pollinators. In a pollination study of the Farallon Islands, just west of San Francisco, all the pollination interactions I observed were due to the immense clouds of seaweed-flies which reproduce amongst the decomposing flotsam on the beaches and rocks. They seem to be just as important along the coast of the mainland as well. They only visit dish- and bowl-shaped flowers.
Coelopid flies occur only on the seashore. They are distinguished by elongate bodies, a low to the ground stance, and thick muscular legs.