March flies belong to the insect family Bibionidae, along with love bugs. About 78 species of march flies are found throughout the U.S. and Canada. They are quite common and often occur in very large numbers.
Female March flies are about one half inch in length, about twice as big as the smaller males. Most species are black and have clear wings. Some species are black with a red or yellow prothorax and have smoky to black wings.
Each female will lay from 200 to 300 eggs. They are placed in the soil in wet marshy areas. The developing larvae feed on decaying organic matter such as dead roots and leaves. In the South the adults begin to emerge in April, rarely in March as the name would indicate. They can be found throughout the spring and summer. Adults live for about one week, feeding on the nectar of various flowers. Adult emergence is continuous over a four to five week period and great swarms may accumulate.
Adults gather in open areas such as yards, meadows and road ways. Often March flies may be seen by the millions, mating in flight. Thus, they are often referred to as “lovebugs”.
In the Gulf States, March flies often occur in such great swarms that they cover the front of vehicles traveling through them. They can clog a radiator causing over heating of the engine. They also spatter and coat the windshield in such numbers that they obstruct vision. If not cleaned off of a vehicle, the finish may be damaged.
March flies are rather weak fliers and are often caught in a persons hair or alight on one’s clothing as the person is walking about their yard. They are often attracted in large numbers to hummingbird feeders. March flies are completely harmless, as they do not sting or bite.