A walk through a disused railway tunnel last week – now arching over a Sustrans cycling route – revealed hundreds of webs attached to the ceiling. Each web was built flat against the brickwork, and they each had two definite and neatly shaped holes which allowed the spider access behind the web. The holes did not correspond to similar holes in the brickwork; rather they were two different entrances to the mortar-filled cracks which ran between the bricks.
I liked the effect of this array of webs – especially with a slightly longer exposure on a windy day, they made quite an abstract pattern.
The webs belong to lace webbed spiders – Amaurobius spp. It is difficult to ID these more precisely because there are two very similar spiders – Amaurobius fenestralis and A. similis. The similis species is more often associated with houses and brickwork which makes this the more likely ID for these colonies. A. fenestralis is more often found beneath the bark of trees.
I went back at night to find out what these spiders looked like – they are quite dark and robust with attractive patterning on the backs. Many were out and patrolling their webs, whilst others remained inside, or just protruding from the entrance holes.
These are quite a common species in the UK and are one of those most commonly mistaken for the false widow – itself vilified beyond reason by the British Press in search of a story. The lace-web weaver can in fact bite if pushed, but there are very few cases recorded and it will be nothing more than a slight nip.
The spiders can often be found associated with the brickwork of houses, and I found similar smaller colonies associated with bridges and other brickwork along the Grantham Canal. If you do come across one, you can gently coax the spider out using a tuning fork, or lightly tapping the web with a twig to simulate an insect. Be careful not to damage the web though – they are the equivalent of a fisherman’s net and are vital to allow the spiders to catch the food they need to survive.