Springtail

Not actually an insect

Springtails are hexapods (six legs) but are no longer classified as insects — they belong to their own class, Collembola, which diverged from the insect lineage over 400 million years ago. They lack wings, have internal mouthparts (rather than external mandibles like insects), and their eyes are simple clusters of lenses rather than compound eyes.

They are among the most ancient land-dwelling hexapods, with fossil springtails known from the Devonian period (400 million years ago) — predating even most insects.

The spring

The name comes from the furcula — a forked, tail-like appendage folded under the abdomen and held in place by a latch (the tenaculum). When threatened, the springtail releases the furcula, which snaps against the substrate and launches the animal up to 10 cm into the air — about 100 times its own body length.

The spring is purely defensive — springtails use it to escape predators (mites, beetles, centipedes), not for locomotion.

Abundance

Healthy temperate soil can contain 100,000 to 400,000 springtails per square meter — making them one of the most numerous macroscopic animals on land. A single hectare of forest soil may hold several hundred million individuals.

This abundance makes them foundational to soil food webs:

• They fragment and consume organic matter, increasing surface area for bacterial decomposition
• They disperse fungal spores through the soil
• They are prey for mites, beetles, centipedes, and other soil predators

Diversity

The 8,000+ described springtail species range from the common grey globular springtail (resembling tiny ball-bearings in leaf litter) to the elongate surface-dwellers to the snow flea (Hypogastrura nivicola) — a springtail that becomes active in winter and is sometimes seen in enormous numbers on snow.