Ed Dolphin writes for the Sid Valley Biodiversity Group.
They are with us throughout the summer, but spider webs become more noticeable on bright autumn mornings as they sparkle with dew drops. Size for size stronger than steel but also more stretchy than rubber, spider silk is one of the most marvellous creations in nature.
Many insects spin silk but most people think of spiders when you talk about webs. This almost magical material can be used to catch prey, protect eggs and young spiderlings, and even to help the spiderlings fly away to find new homes.
Spider silk is a string of protein molecules produced from spinnerets under the spider’s abdomen. A fine jet of liquid protein squirts from the spinneret and sets into a solid thread. Spiders have up to seven different spinnerets that produce different qualities of silk including a woolly form that the spider will plump up by back combing with a special set of hairs on the hind legs.
Fewer than half of the 37 spider families use their silk to spin webs to catch prey. The different web spinning spiders have characteristic forms and patterns so an expert might tell who made the web without even seeing the spider. British spider webs have seven different forms; orb, sheet, tangle, funnel, lace, radial and purse.
The common Garden Orb Weaver produces the familiar webs children and cartoonists will draw that look like the wire pattern on a dartboard, and these decorate shrubs and gaps in fences hoping to catch passing insects.
It takes an orb weaver spider about two hours to produce a web. Swinging like an acrobat from twig to twig to make the radial spokes and then round and round to fill it in. It is worth searching YouTube where there are some fascinating videos of spiders doing this.
If an insect is caught, many spiders will immobilise it with a poison bite and then wrap the unfortunate creature in a silk cocoon to be eaten later. When a web becomes too tatty, the spider will roll it up and eat it to re-use the silk protein.
Other spiders construct sheet and tangle webs that trap prey as they run across. Some spiders, including the Common House Spider, spin a funnel shaped web. They sit inside the funnel and rush out as prey walks across the mouth of the funnel. Some spiders will save energy by finding a hole in the ground or a wall and just lay the radial trip wires rather than the whole funnel. Purse web spiders build themselves a small nest rather like a pitta bread and hide inside, coming out at night to hunt.
The real specialist is the Diving Bell Spider. This remarkable species lives underwater and collects air bubbles in an upturned pocket of web like an old diving bell.
In late summer, you can find balls of silk in sheltered places such long grass and shrubs or under window sills. Inside will be hundreds of spider eggs and then spiderlings, sometimes protected by the mother sat ready to tackle any intruder.
When the spiderlings are ready to disperse some will do so by ballooning or kiting. They will climb to the top of a tall plant and let out a long thread of very fine silk called gossamer. As the breeze tugs at the gossamer, the spider will let go of the plant and float away like a balloon or kite on a string. This can take them miles away and is probably why spiders are among the first creatures to colonise new land such as after a volcanic eruption.
Spider silk can be woven into a very fine fabric, but it takes a lot of spiders to produce enough silk and so spider silk garments are incredibly rare, unlike the spiders’ own masterpieces.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here