Brine flies (Ephydra gracilis) emerge in masses in the Great Salt Lake (Utah, USA). The adult flies can rest on the water's surface. Here, a gull feeding on the flies makes a wake as the flies move out of range of the bird.
Densities of brine fly larvae in the lake rival those of the better known brine shrimp. The larval brine flies feed on periphyton (algae) that grows on stromatolites (biostromes) in waters shallower than 3 m (10 ft). After passing through several instars, the larvae pupate, and then emerge as adults to mate.
Photo: 25 July 2006 from the Antelope Island Causeway.