These are primarily native insects in North America, and occur nearly everywhere.
Springtails are tiny insects that occur most often in damp locations, where they feed on algae, fungi, and decaying plant materials. They become active in early spring and may be seen on snow cover, where they derive their mistaken identity as snow “fleas”. In structures their presence may indicate excessive moisture conditions in walls or crawl spaces, under sinks, or around indoor plants. They appear to be drawn to water, and commonly will appear in vast numbers on the surface of swimming pools, seemingly overnight. The name “springtail” is given due to a sharp projection at the tail end, called a furcula, which may be snapped down onto the surface they are on to allow them to spring into the air for sudden movement. This can be felt if it occurs on human skin, giving the impression that a person was just bitten by something that cannot be seen. In reality, springtails are completely harmless to humans, although allergies and dermatitis have been reported in some people sensitive to their presence.
Springtails are usually less than 2 mm long, and colors range from black to silvery gray, depending on the species. The distinctive character is the furcula attached to the tip of the abdomen, facing forward or backward depending on the species. A common structure-invading group is in the genus Entomobrya, and these also have very long, 3-segmented antennae and hairy bodies. Magnification will be needed to see all these characters.
Characteristics Important in Control:
Control of moisture sources is critical, and within structures the presence of large numbers of springtails may be considered a sign that a moisture problem exists. Since these are primarily outdoor insects they can be prevented by reduction of moisture, removal of mulch or other decaying vegetation, and possibly with an application of a residual insecticide.