Bibionidae

The Bibionidae (march flies and lovebugs) are a family of flies (Diptera). About 650-700 species are known worldwide.

Description

Bibionidae are medium-sized flies with a body length from 4.0 to 10.0 mm. The body is black, brown, or rusty, and thickset, with thick legs. The antennae are moniliform. The front tibiae bear large strong spurs or a circlet of spines. The tarsi are five-segmented and bear tarsal claws, pulvilli, and a well developed empodium. The wings have two basal cells (posterior basal wing cell and basal wing cell), but are without a discoidal wing cell. R4+5 is simple or branched; at most, only three branches of R developed. The leading edge wing veins are stronger than the weak veins of the trailing edge.

Biology

Bibionid larvae grow up in grassy areas and are herbivores and scavengers feeding on dead vegetation or living plant roots. Some species are found in compost. Larvae are sometimes found in pockets in which sometimes up to 200 specimens have been counted. Adults of most Plecia and some species of Bibio do not eat, but subsist solely on the food taken in during the larval stage and drop steadily when in flight until they are a few inches above the ground, hovering slowly. Adult-stage bibionids are quite short-lived, and some species of Plecia (lovebugs) spend much of their adult lives copulating. The male and female (lovebugs) attach themselves at the rear of the abdomen and remain that way at all times, even in flight. Adults swarm after synchronous emergence, sometimes in enormous numbers.