Springtails are a group of organisms that have six legs (hexapods) like insects. However, springtails are not insects, mainly because their mouthparts are enclosed within the head, whereas insects have external mouthparts. Most springtails have a forked appendage (furcula) held under the abdomen that helps them escape predators by catapulting them into the air when sprung against the ground. Hence the name springtails.
Springtails primarily live in moist soil and leaf litter, feeding on microbes and organic material. Most of them breathe through their cuticle because they do not have a tracheal respiratory system. This makes springtails vulnerable to desiccation and dependent on having moisture in their environment. Sometimes their populations boom by the thousands during periods of high moisture, usually provided by excess precipitation or structural leaks.
Normally, indoor environments do not provide enough moisture to support springtail populations unless a structural leak or poor ventilation is present. Springtails will die off once these conditions are fixed. Once remediated, treat voids or crevices with a properly labeled dust or aerosol formulation to knock down springtails faster. If outdoor plant beds are the source of springtails indoors, insecticide granules can penetrate mulch to reach the soil below.
Photo by AJC1, Flickr