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Was the BLOG for the CGCHE Old Skool, a daytime TV view of their lives today, or what they did yesterday and only if they can be arsed to Blog it. But they are mostly lazy so sorry if it is mostly empty but Tosh and Ben do their best to keep it going
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This is Spider Time. Now they appear to be most numerous and busy
at millions of spiderlings that climb to high perches and spin long
filaments of silk by which they are wafted aloft on currents of warm
air and may be carried hundreds or thousands of miles. Probably that
is why there are spiders on lonely Islands, deserts and almost every
part of the world except mountain tops and arctic regions. When we
walk through a woodland these days, cobwebs, strung from tree to tree,
cling to our faces. In the mornings, on lawns and sparkling with dew
drops, we see dozens of filmy handkerchiefs spun by grass spiders. In
gardens and fields we see the marvelous webs of orb-weavers.
There are at least 2000 species of spiders In this country but only a few
families of them build elaborate webs. In each family the females
construct a distinctive type of web and there are four general types: orb
webs, funnel webs, sheet webs, and the irregular festoons built by
house spiders. All of them are built for a purpose: as traps to catch
insects.
One of the truly wonderful performances by any animal is the intricate
web constructed with geometric precision by the big black-and-yellow
garden spider -- one of the orb-weavers -- and If necessary she can
complete it In one hour.
Although the garden spider has eight eyes, she builds a web almost
entirely by touch. Underneath her abdomen are six spinnerets that can
be extended or compressed and used like the fingers of a human hand.
Each spinneret has "faucets" and "spools" connected by tiny tubes to
several types of glands. Each type manufactures. In liquid form, a
different kind of silk. Filaments of the several kinds are used singly or
in combinations for specific purposes In certain locations. Most
strands are composed of more than one filament. They solidify and
become stronger than steel when drawn out and exposed to the air.
The sheetllke webs that sometimes appear overnight on lawns and
meadows, especially in autumn, are built by the funnel-web or grass
spider. Each sheet extends outward from a funnel-like opening
beneath which the spider lurks in waiting for grasshoppers and other
insects that may alight upon It. She constantly enlarges the web and. If
undisturbed, it may become a square yard In area. In autumn, after
laying eggs In one or more sacs that are hidden In secluded places, she
dies. The spiderlings emerge in spring and their delicate webs may be
seen in May.
The common house spider is detested by housewives because it
sometimes spins a web near the ceiling in a corner of some room or
closet. Generally, however, they frequent dark less-used places such as
attics, cellars, barns, sheds, or under porches; and are useful as
destroyers of flies, mosquitoes and moths. A typical web, usually built
at night, has a central sheet of densely woven silk which serves as a
hiding place and is anchored by numerous guy lines that are long and
strong. This spider is one of the large family known as the comb-
footed spiders. On each of the hind pair of legs they have a row of
curved bristles used to fling strands of silk over any insect that
blunders into the web and render it helpless. They have been known to
capture, kill, and suck the body liquids from a baby mouse.
In autumn, most of the gossamers In fields and drifting through the air
were spun by the tiny Balloon Spiders. Sometimes, borne away by
those streamers, they are found far above the clouds or far out at sea.
Threads of gossamer, threads of life, fairy bridges by a spider's wife
The construction of a wheel web
How does an orb web spider make its web?
The most difficult part seems to be the first thread. The solution is simple. The spider releases a sticky thread that is blow away with the wind. If the breeze carried the silken line to a spot where it sticks the first bridge is formed. The spider cautiously crosses along the thin line reinforcing it with a second line. She enforces the line until it is strong enough.
After this the spider constructs a loose thread and constructs an Y shaped thread. These are the first three radii of the web. A frame is construct to attach the other radii to. The radii are completed. The distance between them a so wide that the spider can span the width. Now the sticky thread is woven between the radii and the web is completed. After a night of hunting the web becomes worn out. The spider removes the silk in the morning only leaving the first bridge line. After a daytime rest the spider construct a new web in the evening. If the catch was low and the web is not heavily damaged the web may stay during the day and be reused after minor repairing.
There are a lot of variations on this type of web. The web shown is made by the orb web spiders. Spiders of other families construct other types of web
What is the thread made of? It is a protein of a molecular mass of 30.000 Dalton in the gland. Outside the gland it polymerizes to a molecule named fibroin with a molecular mass of around 300.000 Dalton. It is still not clear what activates polymerization process.
Why does the silk made of protein not decompose by fungi and bacteria like all other proteins? We conserve protein by cooking, salting, drying or adding acid. In spider silk there are three substances that are important for its durability: pyrolidin, potassium hydrogen phosphate and potassium nitrate. Pyrolidins can be found in dyes and plant poisons and are very hygroscopic (binds water). This substance prevents the thread from drying out. Pyrolidin is also found in high concentration in the glue of catching threads. Potassium hydrogen phosphate makes the thread acidic and prevents fungal and bacterial growth. A low pH causes denaturation (become insoluble) of proteins. A phenomenon we can observe in sour milk. Potassium nitrate prevents this and the proteins are salted which prevents bacterial and fungal growth.
The thread of the orb web spider Araneus diadematus is very elastic and can be stretched 30 - 40% before it breaks. Steel can be stretched only 8% and nylon around 20%. In the picture one can see the thread of the spider Stegodyphus sarasinorum that, because of its weaving technique, can be stretched up to 20 times it original length.
A lot of orb weaving spiders recycles their web. The weaving of a web takes up a lot of the spider's resources. Since they need to renew their web regularly, they eat the silk. Only the main thread of the web is left intact. They usually weave a new web in the morning
Applications of spider silk
Spider silk was and is used for several applications. Polynesian fishermen use the thread of the golden orb web weaver Nephila as fishing line. In the New-Hebrides spider web was used to make nets for the transportation of arrow points, tobacco and dried poison for the arrow points. Some tribes in New-Guinea used webs as hat to protect their head for the rain
During World War II the threads of Araneus diadematus, Zilla atrica, Argiope aurantia and other orb weavers were used as hairs in measuring equipment. The Americans used the threads of the black widow (Latrodectus) in their telescopic gun sights.
In 1709 a Frenchman, Bon de Saint-Hilaire, demonstrated the possibility to make fabric from silk. Many cocoons were boiled, washed and dried and the thread was collected with fine combs. Some socks and gloves were produced. A study to the economic yield of this method revealed that this would never be profitable. It was calculated that 1.3 million spider cocoons were needed to produce one kilogram of silk.
In Madagascar there were some attempts to milk Nephila's for the production of silk. By hand a thread was pulled out of the spinner of the spider. If the spider was exhausted she was put back in the forest and the next spider was milked. The gathered silk had a beautiful golden color. This project was also banned because of many problems. Nowadays one tries to produces silk in factories.
christ got bored after 3rd line!
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