Lesser dung flies

Overview

Sphaeroceridae, called lesser dung flies, is a family of very common, very small, “acalyptrate” flies. There are more than 1,300 species in 125 genera worldwide, about 280 species in 30 genera in North America north of Mexico, and at least 10 species in 10 genera in Minnesota. They occur in all parts of the world without permanent ice cover. They are very common but rarely noticed.

Adults are found near manure and other refuse. The larvae graze on microbes and are found in all kinds of decaying organic material.

Description

Adults are blackish or brownish and range in size from 1⁄32″ to 3 ⁄16″ (1.5 to 5.0 mm) in length. There is a frontal suture on the face immediately behind the bases of the antennae. The antennae have three segments. The second segment does not have a longitudinal suture. There is a large bristle on the upper (dorsal) side of the third segment. There is no lobe (calypter) at the base of the forewing. The wings are clear, rarely spotted. The vein behind the leading edge (costa) of the forewing (subcostal vein) is incomplete, fading out before connecting with the costa. The first segment of the hind foot (tarsus) is thick and is shorter than the second segment.