Spider webs are miracles that spiders weave in the middle of ordinary human lives. Spiders have been around for at least 380 million years and scientists estimate that there may be about 180,000 spider species. Spiders are not insects, but what scientists classify as arachnids, a classification that includes daddy long legs, scorpions, mites, and ticks. Insects have six legs, wings, and antennae. Spiders have eight legs.
Spiders are Self- Reliant
Spiders build their own homes and capture their food supplies. Spiders are the only creatures that incorporate silk into their daily lives by spinning webs out of silk that they produce with their own bodies. They use their webs to travel or “balloon” from one place to another, as protection at the entrance of their dwellings, to encase egg sacs, and to trap insects for food.
The Composition of Spider Webs
Spiders have seven pairs of silk spinning glands called spinnerets that are located either in the middle or at the end of their abdomen. Each spinneret is unique and the spider uses each to manufacture different kinds of silk. Disk silk leaves a zigzag pattern and strengthens the dragline. Safety line silk gives the spider an anchor. Orb web silk gives the web strength and stretchiness. Sticky catching silk traps and captures prey. Swathing silk wraps and immobilizes prey. Tangling silk tangles prey. Egg sac silk keeps baby spiders safe. The spider manufactures the silk as a liquid, but it comes from its glands as solid silk fibers. The Nephila spider’s silk is the strongest natural fiber known to humans and humans use it to make tote bags and fish nets.
The Specific Spider Web
Tangled spider webs consist of a shapeless jumble of threads attached to a support such as the corner of a ceiling. Cobwebs are tangled webs that have collected dust and dirt. Black and brown widow spiders and common house spiders make tangled webs. The orb web, that looks like a wheel with spokes, is the most common spider web. Spiders that weave the orb web include humped spiders, bolas spiders, silk spiders, and shamrock spiders.
Sheet webs are composed of flat sheets of silk between grass blades or shrub or tree branches. The doily spider, the filmy dome spider and the platform spider spin sheet webs. Gum-footed webs are made up of tightly woven silk strands attached between two branches. When an insect is trapped in the web, its struggles break the lines and move the web up, lifting it off the ground so it can’t escape. Redback spiders make gum footed webs. Horizontal Line webs are composed of one line of sticky droplets that stretch across vegetation. When an insect hits the line the loose silk tangles the prey. Cribellate and pea sized spiders make these webs.
Bolas spiders design bolas spider webs. The spider sits on a horizontal line and spins a single line with a sticky silk tip that it dangles from its leg. When its prey comes toward it,the spider swings the silk in a circle and captures it. The triangle spider creates triangle webs. It waits at one end of the web for an insect to land and shakes the web so the insect can’t escape.
The Historic Spider Web
King Robert the Bruce, crowned King of Scotland in 1306, had a mission to free Scotland from the English Army. Defeated in battle, Bruce escaped and hid in a cave for at least three months. Discouraged, he thought about leaving Scotland for good. While in hiding, he watched a spider building a web over the cave entrance. The spider constantly fell as it tried to weave its web, but the spider kept working and finally finished the web. Robert the Bruce decided that he would persevere like the spider and continue to fight for Scottish independence.
The Enduring Spider Web
In December 2008, British paleobiologist Martin Brasier of Oxford University announced that a 140 million year old web had been found in a small piece of amber. An amateur fossil hunter had picked up the fossil on a beach on England’s south coast two years earlier.
The Adaptable Spider Web
On November 21, 2008, two spiders on the International Space station after a few trial days of weightlessness, wove a symmetrical web. Michael Fincke, the space station’s director, radioed the news to Mission Control.
The Artistic Spider Web
The artistic spider web is discovered in ordinary gardens, woods, and trees and it transforms everyday life into dew drops sparkling in sunshine.
References
Paul Hillyard, The Private Life of Spiders, Princeton University Press, 2008.Rainer F. Foelix, Biology of Spiders , Oxford University Press, USA, 2nd Edition, 1996.
Herbert W. Levi, Lorna R. Levi, Spiders and Their Kin: A Golden Guide from St. Martin’s Press, Golden Guides from St. Martin’s Press, 1st Edition, 2001