26 April 2014

Cave Spider

The picture below was taken in the exit tunnel of Treak Cliff Cavern, at Castleton in Derbyshire.  It shows a cave spider (Meta menardi).



The cave dwelling spider with the Latin name Meta menardi is fairly widespread throughout the UK, and not uncommon.  A colony may comprise just a few individuals or several hundred.  It prefers very low light levels or total darkness and may retreat deeper into the cave in winter months, moving to nearer the entrance in spring.  The cave spider is one of Britain’s biggest  spiders, reaching up to 1.5cm body length, with a 5cm leg span; females are larger than males.  They are not dangerous to humans, and are usually good natured but may nip (with no ill effects) if handled roughly.

Webs are spun in shadow or hollow pockets in the rock to catch prey which enters the cave such as fungus gnats, woodlice and millipedes.  Cave spiders produce teardrop shaped egg sacs, which are suspended from the cave roof.  When the baby spiders hatch in spring, they are attracted to light, which means they move outside the cave to find new areas to colonise.  By mid-summer, they become photophobic (hate light), so move back into caves or tunnels.  The adult spiders can live for as long as three years.

The European Society of Arachnology voted the cave spider (Meta menardi) “European spider of the year 2012, and a German cave research group named it "cave animal of the year" in 2012 as well! 

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