The Living World - Cave Spiders

Cave Spiders are one of the largest spiders found in the United Kingdom, with adults measuring up to 5cm legspan and 15mm body length. For arachnophobes they are probably the stuff of nightmares, but to spider lovers they are creatures of great beauty with shiny brown abdomens rather like polished conkers. There are two species found in Britain, Meta bourneti and the slightly more common Meta menardi. Both species like dark places, but only Meta bourneti has been found in the damp cellars of Witley Court. Cave spiders can be identified by their large teardrop-shaped white egg cases, about the size of a damson, which are suspended on a silk thread from the roof of their dwelling. When the spiderlings hatch (and there can be 100 spiderlings in a single case) they are attracted to light, unlike the adults which are strongly repelled by light. This helps the young find new areas to colonise. They release silken thread from their spinnerets and drift on these threads which are caught up and blown by the wind, so they can travel long distances. Once they land they produce a small orb web in which they catch insects. In mid-summer the spiderlings seek out dark caves or tunnels in which to spend the rest of their lives. Spiderlings have two moults before they reach the adults, and cave spiders feed on small insects and woodlice which they catch in their fine orb webs.