Ground Spiders

Details

Ground spiders are a broad group of mainly ground‑dwelling spiders, most commonly placed in the familyGnaphosidae. Rather than building large aerial webs, they hunt by running and ambush across soil, leaf litter and stones, where they prey on small insects and other arthropods. They are important “on‑foot hunters” in many grassland, farmland and garden ecosystems.

Basic Biology

• Scientific scope: Family Gnaphosidae – ground spiders (e.g. Gnaphosa spp.)

• Size: Typically small to medium, about 5–20 mm body length.

• Longevity: Around 1–2 years; some temperate species survive one or more winters.

Ecology & Behaviour

Most ground spiders are nocturnal. By day they hide under stones, bark, debris or in short silk retreats; at dusk and night they roam in search of prey. They catch beetles, ants, juvenile crickets and other small arthropods using speed and relatively good vision rather than capture webs. Some species build short silk tubes or sheets as shelters at ground level.

Morphology

Many have a slightly flattened, elongate‑oval body with robust legs for running. Colours tend to be brown, grey or dark, often with subtle mottling that provides camouflage. In gnaphosid spiders the anterior spinnerets are somewhat cylindrical and can protrude, a helpful field character.

Venom & Human Interactions

Ground spiders possess venom to subdue prey, but bites to humans are usually minor, causing brief pain, redness or itching. They are shy and prefer to retreat rather than bite, and are not considered medically important in healthy people.

Ecological Role

By consuming many ground‑dwelling insect pests, ground spiders contribute to natural biological control in fields, lawns and gardens. Maintaining leaf litter, stones and other microhabitats, and limiting insecticide use, helps support their populations and overall arthropod diversity.