Spider web

Spider webs have existed for at least 100 million years, as witnessed in a rare find of Early Cretaceous amber from Sussex, in southern England.

[3] However, the word "cobweb" is also used by biologists to describe the tangled three-dimensional web[4] of some spiders of the family Theridiidae.

[citation needed] When spiders moved from the water to the land in the Early Devonian period, they started making silk to protect their bodies and their eggs.

Webs allow a spider to catch prey without having to expend energy by running it down, making it an efficient method of gathering food.

However these energy savings are somewhat offset by the fact that constructing the web is in itself energetically costly, due to the large amount of protein required in the form of silk.

Due to the incredible strength of spider silk, scientists are currently studying it in the hope of creating a super-tough material with the same abilities.

[3][9] Most commonly found in the sheet-web spider families, some webs will have loose, irregular tangles of silk above them.

These tangled obstacle courses serve to disorient and knock down flying insects, making them more vulnerable to being trapped on the web below.

[10] It is reported that several Nephila pilipes individuals can collectively construct an aggregated web system to counter bird predation from all directions.

It makes a spiral of non-sticky, widely spaced threads to enable it to move easily around its own web during construction, working from the inside outward.

Then, beginning from the outside and moving inward, the spider methodically replaces this spiral with a more closely spaced one made of adhesive threads.

After the spider has completed its web, it chews off the initial three center spiral threads then sits and waits, usually with the head facing downwards.

[16] If the web is broken without any structural damage during the construction, the spider does not make any initial attempts to rectify the problem.

Several types of water-dwelling spiders rest their feet on the water's surface in much the same manner as an orb-web user.

When an insect falls onto the water and is ensnared by surface tension, the spider can detect the vibrations and run out to capture the prey.

The diving bell spider and Desis marina, an intertidal species, use their web to trap air under water, where they can stay submerged long periods of time.

[21] In traditional European medicine, cobwebs were used on wounds and cuts to reduce bleeding and aid healing.

[24] During the 1st century BC, the Roman army used spider webs as field dressings, which also served as a fungicide.

[26] In northeastern Nigeria, cow horn resonators in traditional xylophones often have holes covered with spider webs to create a buzzing sound.

[28] Development of technologies to mass-produce spider silk has led to the manufacturing of prototype military protection, wound dressings and other medical devices, and consumer goods.

Presumably these toxins help immobilize prey, but their function could also be antimicrobial, or protection from ants or other animals that steal from the webs or might attack the spider.

[47] After the launch on July 28, 1973, and entering Skylab, the spiders were released by astronaut Owen Garriott into a box that resembled a window frame.

[49] Later experiments indicated that having access to a light source could orient the spiders and enable them to build their normal asymmetric webs when gravity was not a factor.

In films, illustration, and other visual arts, spider webs may be used to readily suggest a "spooky" atmosphere, or imply neglect or the passage of time.

Some observers believe that a small spider is depicted on the United States one-dollar bill, in the upper-right corner of the front side (obverse), perched on the shield surrounding the number "1".

This perception is enhanced by the resemblance of the background image of intertwining fine lines to a stylized spider web.

Artificial spider webs are used by the superhero Spider-Man to restrain enemies and to make ropes on which to swing between buildings as quick transportation.

Some incarnations of the character, such as the version in the Sam Raimi film trilogy and Spider-Man 2099, are shown to be able to produce organic webs.