Charlie, Milton Keynes asked:
How do spiders build their webs? Are they brilliant mathematicians?
We put this question to Todd Blackledge, Associate Professor of Biology at the University of Akron:
"Surprisingly, despite how elegantly symmetric orb webs are, they don’t have a map of the shape of the web. Instead, they have genes that control how they move individual legs as their manipulating silk thread and how to interconnect silk threads. It all starts off with a bridge thread. So a spider can suspend its web in mid air by releasing a very lightweight silk thread until it snags on something such as a tree on the other side of the trail you're walking on. That bridge thread then forms the core of the web. The spider is able to move out and begin to build an outer framework for the web, at the same time as it establishes what are called the radial threads, those you can think of as the spokes on a wagon wheel. And then once this framework is done, the spider then produces a temporary spiral, so it starts at the centre of its web and this temporary spiral acts as a physical guide for the spider to then spin the final gluey capture spiral. And the spider starts at the outside of the web, follows that temporary spiral and essentially paints itself into a corner in the centre of its web. They actually use their legs to measure the distances. So if you watch an orb spider spinning its web, it’s reaching out with one set of legs to touch the temporary spiral and then using its hinds legs to then position the sticky spiral. So spacing between rows of silk is going to change as the spider matures and the length of its legs grows longer and longer."
My understanding is that a spider releases a long, continuous stream of very light thread that wafts away on the breeze. The spider regularly tests the tension on the silk so that it can tell as soon as part of the line snags another remote surface - a twig on a nearby branch for instance. The spider tightens, ties down and then walks across this line, counting its steps so that it "knows" how long it is. Securing the other end it then back-counts steps to what would be the middle of this line and drops a perpendicular to form a T shape, which it attaches to the ground or another object vertically below. This creates the initial scaffold for the web, which the spider then "fills in", again using step-counting to log distance.
Q. How do spiders make webs?
I wonder why alcohol and nicotine are not represented? After caffeine they're almost certainly the most sued human drugs...
Don't spiders just go online and order them from the world wide web ? *groan* neilep, Sun, 18th Oct 2009
That's very funny - I especially like the alcohol spider, but the crack spider is pretty cool too! chris, Sun, 18th Oct 2009
Hee hee !!.. crack Spiders bitch !! neilep, Sun, 18th Oct 2009
After making a T shape I think spiders make the first few circular strands out of a non-sticky thread, then filling in the rest of the web with the sticky prey catching thread.
I've got a further question––since not all spiders weave a spiral web (I have a pet Tegenaria Duellica or Giant House Spider that weaves a tunnel web) is this determined by the length of a spiders legs, as well? In other words, if a spider's legs are too long would spinning a spiral web leave spaces too large to capture its prey?
Urg... of all my Fathers and Mothers creations, he and she had to create that beast. Mr. Scientist, Wed, 18th Nov 2009