Springtails have been very abundant this year, with a multitude of calls coming in on springtail infestations. So what are these bizarre little arthropods, what do they do, and what can we do to manage them?
First off, let’s highlight the unusual classification of the springtails. Despite having six legs and an exoskeleton, they are considered separate from the insects, and belong to their own class – Collembola. Both the common name and scientific name reference structures on the belly, though they refer to different structures. “Springtail” touches on the furcula, a fork-shaped “tail” that is usually folded tightly against the belly and held in place by a clasp-like structure called a retinaculum. When enough force is applied to the furcula to break it loose from the retinaculum, it slams into the ground hard enough to catapult the springtail long distances – up to ¾” or so (which is a long way for a 1/32” springtail to jump). “Collembola” translates from Greek as “glue stopper,” in reference to an evertible, tubelike structure near the base of the abdomen called a collophore (“glue bearer”) that is thought to be involved in controlling jumps, and possibly in regulating body moisture. They share the subphylum Hexapoda with the well-known class Insecta, as well as the less known Diplura and Protura, and can be reliably distinguished from the others by their jumping structures on the abdomen, as well as distinguished from insects by having mouthparts enclosed within a pouchlike structure on the head rather than external. Fossil evidence suggests that springtails evolved to essentially their current form roughly 400 million years ago, so they are a very ancient group. As a rule, they are small, with most springtails measuring in at one or two millimeters long, though they can be larger or smaller. Most springtails are dark colored, with shades of brown, gray, black, and dark purple being common, though different species can be just about any color. Body shape can range from oblong to globular.
So what do springtails do? Aside from springing, the best-studied part of springtails’ lives seems to focus on their feeding biology. It can be tempting to think that their feeding cannot be all that important in the grand scheme of things, given their diminutive size. However, they make up in numbers what they lack in size, with suitable habitats often harboring springtail densities of around 100,000 individuals/m2, which puts them on par with nematodes, mites, and crustaceans for most numerous macroscopic animals on earth. Most are scavengers, feeding on dead plant matter, fungi, bacteria, pollen, or any other form of organic debris they can find, a few species are predators, and a few are intermittent agricultural pests that attack the roots of plant seedlings. The scavengers play a big role in nutrient cycling in soil, breaking down organic debris and liberating nutrients that can then be used as plants. Their feeding activity seems to stimulate the growth of mycorrhizae – the symbiotic fungi that help plants utilize nutrients in the soil – while they are thought to be able to suppress the growth of pathogenic fungi on plants. By consuming mold spores, pollen, and other debris, it’s plausible to think they might clean up environmental allergens as well, though I have not seen research to confirm this hypothesis. However, arthropod exoskeletons, hairs, scales, and droppings can be allergenic, so springtails may become allergens themselves. To my knowledge, there have been no confirmed cases of springtails behaving as parasites on people or pets, though false alarms connected to delusory parasitosis are not unheard of. When springtails find their way indoors, they can be a nuisance, but are not a danger.
So what can you do about springtails? A great starting point is to use springtails’ primitive nature and tiny size against them. Because they are so small, springtails are able to rely entirely on cuticular respiration, meaning they breathe through their skin. If oxygen and carbon dioxide can pass through their exoskeleton, then water can too, meaning springtails are susceptible to drying out. Reducing moisture and humidity in the area directly around the springtails can drive them away or kill them outright. Exclusion by sealing cracks and crevices that allow springtails to enter from the soil outside and maintaining a mulch-free barrier around a building can help lock springtails outside. Considerable research from Dr. Mark Boetel at North Dakota State University has shown that many pesticides can reduce feeding damage from springtails in sugar beet fields, though our experience at Guardian has been that no chemical is effective enough to deliver acceptable results when treating nuisance populations of springtails, especially when they move indoors.