"Mathematics is the expression of natural patterns in language humans can understand. Crystals, the half-life, and the spiderweb have all been 'mathematical' entities since millions of years before the first person understood that one can simulate patterns from manipulating arbitrary quantities. Mathematics is an expression of the truth of nature.
Atoms find one another in spaces too small for light. Bees have discovered the most efficient shape in the world; they use it to grow eggs.
Each species of spider is born with the ability to spin a certain type of web — be it a funnel, a sheet, or an orb. The force of an insect hitting the center of an orb web is comparable to that of an airplane hitting a tennis net1. That it doesn't explode in a sparkling shower of fibroin is thanks to the aerodynamics of the individual strings.
You could balance a spiderbrain on a needletip, you know.
Chemistry
The web silk does not become fibroin until it leaves the spider's body. Before then, it's a protein with a molecular mass of roughly 30,000 Dalton. Upon being ejected by the spinners, it polymerizes into the substance we know as fibroin, a new protein whose molecular mass has increased tenfold. To this day, polymerization of web silk is a mystery.
Bacteria and fungi love protein. Decomposition is the work of spores and flagellates. Spider web is a protein, but it doesn't decay. There are cobwebs thousands of years old — fibroin ages well.
Spider silk is full of pyrolidin, potassium hydrogen phosphate and potassium nitrate. Pyrolidins bind water (if you're a scientist, you'd say they're hygroscopic), preventing the web from drying out — you can also find them in plant poisons and natural dyes. It's more concentrated in the sticky catching threads. The Potassium Hydrogen Phosphate makes the web acidic and resistant to fungal and bacterial growth. The low pH of acids causes the denaturation of proteins, a phenomenon you've observed firsthand if you've ever opened a carton of sour milk. This is where the Potassium nitrate comes in: it acts like salt.
Steel is one of the strongest metals on the planet. Stretch it by 8% and it breaks. Nylon is a bit more elastic: it'll go about 20%. The web of an orb-weaver is good for 30-40%. The thread of the Stegodyphus sarasinorum is constructed in a weave and will stretch to twenty times its original length — for the sake of continuity, that's 2,000%.
Biology
Different spiders have different glands for the production of web proteins. Across the vast tapestry that is spider, there are seven common glands. Some spiders have more than others; none have all seven.
Your typical spider has three pairs of spinners. Your typical spinner contains thousands of tubes, all connected to the protein-secreting glands. We're dealing in tenths, hundredths of micrometers here — the thinnest strand of spider silk ever measured came in at roughly .02µm. We see spider web only because it shines in the light.
The glands are a varied and complex bunch:
Tubiliformes make thread for cocoons;
Aciniformes make thread for bundling up prey;
Ampulleceae (major and minor) make non-adhesive walking thread;
Aggregata make sticky material for the threads;
Pyriformes make outer anchoring threads;
Coronatae make the core of the adhesive threads, which are coated in the secretions of the aggregata.
Imagine building a house out of your own secretions. The strain on your body would be large.
Orb-weavers eat their own webs to conserve resources, ingesting the night's ragged ends to be recycled for the next morning's refinishing.
Architecture
The subtleties of spiderweb construction are comparable to those of human homes. I'm assuming you don't want to read a book; this will be kept simple.
Virtually all spiderwebs fall into one of three categories: orb, sheet, spatial.
Big, prototypical yarn webs you buy at the party store are imitations of orb webs: the concentric mesh sheet with the inward-running spiral.
A sheet web is a somewhat rarer phenomenon — the three-foot ladder web of the rainforest bounces prey off like a sideways trampoline and deposits them in a silk reservoir for later consumption. The pride and joy of the funnel web spider is a sheet.
The spatial web is the work of a disorganized spider: a big messy tangled clump of thread.
Of course, there are exceptions. The trapdoor spider fits the top of an earth hollow with a flat rock and attaches a trip wire.
The construction of suspended webs is a rather cavalier process. In the case of orb and sheet webs, the spider finds two upright structures from which to hang the top thread. Instead of depositing a strand at one structure and walking to the other, spinning as she goes, she stands there and lets loose, hoping that luck and breezes will guide her line to a convenient place. Once this is accomplished, she reinforces the line with thicker thread and descends from its center, creating a Y shape from which the remainder of the web radiates. Non-adhesive and adhesive strands are deposited accordingly: usually the mesh structure is non-adhesive walking rope while the inward spiral holds prey in place.
Human uses
When we are children, we play with spider web. We weave it in our hands and listen to the tiny pops when the tension of our moving fingers gets to be too much. We recognize from an early age that this thread which is too thin to see is strong enough to impede movement. And when we grow up, our spirit of enterprise obligates us to find uses for it besides cat's cradling.
Fishermen casing the waters off the coast of French Polynesia use the golden thread of the Nephila as a fishing line.
During the Second World War, Americans used the thread of the black widow as hairs in telescopic gun sights.
At the beginning of the eighteenth century, Frenchman Bon de Saint-Hilaire made gloves from fabric refined from spiderweb. In this process he found that one cannot possibly refine spider-silk profitably: he calculated that he'd need over a million egg cases to produce a single kilogram of fabric.
1 From ABC — fourth source.
Sources
Conservation Biology
www.conservation.unibas.ch.team/zschokke/spidergallery.htmlEd Nieuwenhuys, "The Spider Web and Thread."
www.xsforall.nl/~ednieuw/Spiders/InfoNed/webthread.htmlKnowledge Adventure, Inc.
www.nides.bc.ca/Assignments/Insects/Spiderwebs/htmABC
www.abc.net.au/science/k2/moments/s37273.htm everything2.com/index.pl?node_id=1805995fibroin:
everything2.com/title/fibroinI do wonder about the spores, algae, fungi, b subtilis, lichen, aeroplankton and webs?
...............and the computer?...........web, ..........
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