Spider Silk
Spider Silk
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Some spiders use silk to colonise new areas. On fine days in late summer or autumn tens of thousands of small money spiders climb to the tops of blades of grass or fence posts and spin strands of silk. As the wind catches the silk the spiders become airborne and drift along with the breeze. This ‘ballooning’ allows the spiders to travel huge distances and up to astounding heights. Weather balloons over 1000m up in the atmosphere have caught ballooning spiders!
Did you know that the web of an average Garden spider (Araneus diadematus) contains up to 30 metres of silk!
Pound for pound, spider silk is the toughest fiber in the world-rivaling even steel. Spider silk is also known as-gossamer. A single spider can produce up to seven different varieties of silk. Some are stiff and strong, acting like girders to hold up a web. Others are extremely elastic or sticky to entangle prey. Strength in combination with elasticity makes spider silk amazing.
The study of spiders is called araneology.
Not all spiders weave webs.
Spiders do not stick to their own web because only the central spiral part of the web is sticky, not the spokes. The spider knows where to tread!
Webs lose their stickiness after about a day due to factors such as dust accumulation and exposure to air. In order to save energy the spider eats its own web before making a new one so the protein used for the silk threads is recycled.
Types of spider silk and its uses
Dragline silk are used to connect the spider to the web, as safety lines in case a spider should fall and as the non-sticky spokes of the web. Dragline silk is the strongest kind of silk because it must support the weight of the spider.
Capture-spiral silk: Used for the capturing lines of the web. Sticky, extremely stretchy and tough.
Tubiliform silk: male spiders weave sperm webs on which they deposit sperm and subsequently transfer it to their front palps, ready for placing on a females genital organs. Some species make a web and coat it with sex pheromones to attract a mate. Used for protective egg sacs. Stiffest silk.
Aciniform silk: Used to wrap and secure freshly captured prey. Two to three times as tough as the other silks, including dragline.
Minor-ampullate silk: Used for temporary scaffolding during web construction
Swathing silk for the wrapping and immobilisation of prey.
Webs for catching prey using sticky silk-it is elastic toprevent the prey from rebounding off the web. Shelters such as burrows or nests.
Parachuting or ballooning which is used to aid the dispersal of young and to find new areas as a food source. Silk is released and is caught by the wind to lift the spider up into the air-flying spiders!
Spider silk is incredibly tough and is stronger by weight than steel.
Quantitatively, spider silk is five times stronger than steel of the same diameter. It has been suggested that a Boeing 747 could be stopped in flight by a single pencil-width strand and spider silk is almost as strong as Kevlar, the toughest man made polymer.
Human Use
1. Peasants in the southern Carpathian Mountains used to cut up tubes built by Atypus and cover wounds with the inner lining. It reportedly facilitated healing, and even connected with the skin. This is believed to be due to antiseptic properties of spider silk (which is made of protein).
2. Some fishermen in the indo-pacific ocean use the web of Nephila to catch small fish.
3. The silk of Nephila clavipes has recently been used to help in mammalian neuronal regeneration.
4. spider silk was common to use spider silk as a thread for crosshairs in telescopes, microscopes and similar optical instruments at one time.
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