Gnaphosidae

Common Name

Ground Spiders

Overview

The family Gnaphosidae consists of over 2,400 species of spiders distributed worldwide, known commonly as ground spiders. These arachnids are predominantly terrestrial and are often found under stones, leaf litter, and other natural debris.

Taxonomy

Key Characteristics

  • Size : Small to medium-sized, usually ranging from 2 to 15 mm in body length
  • Coloration : Typically brown or black, sometimes with lighter patterns
  • Body Structure : Cylindrical abdomen, robust cephalothorax
  • Eyes : Eight eyes arranged in two or three distinct rows
  • Legs : Prominent, powerful legs tailored for swift movement

Life Cycle

  • Egg : Laid in silken sacs, often hidden in crevices or under rocks
  • Spiderling : Hatch and disperse from the egg sac, undergoing several molts
  • Juvenile to Adult : Development involves multiple moulting stages, with adults reaching sexual maturity in a few months to a couple of years depending on the species
  • Reproduction : Males transfer sperm to females using specialized appendages called pedipalps

Behavior and Ecology

  • Habitat : Prefer terrestrial habitats such as under rocks, logs, and leaf litter
  • Feeding : Predominantly nocturnal hunters, preying on insects and other small arthropods
  • Web Construction : Do not spin webs to capture prey; instead, they engage in active hunting
  • Defense : Use speed and camouflage to avoid predators

Notable Species

  • Gnaphosa fontinalis : Often found in Europe, known for its preference for moist habitats
  • Drassodes cupreus : Common in North America, notable for its iridescent exoskeleton
  • Callilepis nocturna : Identified by its nocturnal habits and preference for sandy soils

Conservation

  • Status : Most species are not considered endangered
  • Threats : Habitat destruction, pollution, and climate change

Significance to Humans

Fun Facts

  • Some species of Gnaphosidae can run quickly to escape predators.
  • They are often mistaken for wolf spiders due to similar appearances.
  • Certain species exhibit interesting maternal care behaviors, protecting their egg sacs and spiderlings.
  • Ground spiders are adept at squeezing into tight spaces due to their cylindrical body shape.