Seaweed flies

Definition

Members of the family Coelopidae (Diptera), small to medium-sized flies whose larvae develop in decaying brown algae (wrack) deposited along shorelines. Adults are typically dull gray or brown with a characteristically humped thorax, and are strongly associated with coastal marine habitats where they contribute to nutrient cycling in detritus-based food webs.

Etymology

From 'seaweed' (marine macroalgae) + 'flies' (insects of order Diptera), referring to their obligate ecological association with decaying algal wrack.

Example

Fucellia maritima, a common European seaweed fly, completes its entire larval development within decomposing kelp washed up on rocky beaches, with dense larval aggregations accelerating the breakdown of algal polymers.

Synonyms

• kelp flies
• wrack flies

Related Terms

• Coelopidae
• Fucellia
• wrack
• Detritivore
• marine insect
• intertidal ecology
• Diptera

Usage Notes

The term is sometimes applied loosely to any flies found near seaweed, but properly designates only the family Coelopidae. Not to be confused with 'seaweed midges' (family Chironomidae, subfamily Orthocladiinae), which are non-biting midges also associated with marine algae but belonging to a different dipteran lineage. The family is sometimes called 'kelp flies' in North American usage.