Kelp
Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera.
Coelopa frigida
The fly oviposits in dead kelp that washes up on beaches. This is the only place it lays eggs, and it can do so on many species of kelp and seaweed, including species of "Laminaria" and "Fucus". A female fly lays up to five clutches of 80 eggs each. The larvae feed upon the bacteria coating the dead kelp. The life cycle is about 11 or 12 days long.