Orb Weaving Spiders

How does a spider spin its web? Orb weaving spiders make the most familiar webs of all. Orb webs are circular, anchored between two objects. They consist of spokes radiating from a center and a spiral. Garden Orb Web Spider , has a drawing of an orb web with the various parts labelled. Spicy, the friendly backyard spider, demonstrates how this type of web is spun. Initially, the spider constructs a bridge line between two objects, which will support the web. After reinforcing the bridge with a second line, the spider attaches a thread in the middle and drops straight down forming a triangle. Then, the radii or spokes are woven into the web. The web is completed with the addition of the capture spiral.

For a more in-depth description of the building process of orb webs, an excellent site is Orb-web Construction in Spiders. First, look at Web Construction in Araneus Diadematus or common garden cross spider. The pictures reveal the movement of the spider as it builds the web between two sticks (the supporting structure). It is interesting to see the web take shape. After the frame is built (hub and radii), the spider switches silk. Up to this point, a tough non-sticky silk is used. The capture spiral is constructed using a sticky, more elastic silk starting from the outer edges of the web, moving towards the middle. When completed, the spider sits in the centre waiting for his/her lunch. Next, move on to Spider Web Construction Gallery to see a variety of orb webs and how they are spun.

Todd Blackledge's research site hosts webs of orb weaving spiders with an interesting addition-a stabilimenta. A stabilimenta is simply thick white silk woven into the web. The design of the stabilimenta can vary. It can be linear or disc shaped or the form of a cross. Why do spiders spin stabilimenta into their webs? No one really knows for sure but several theories have been advanced.

1. Camouflage of the spider.

2. Means of startling predators

3. A warning that the web is there.

4. To attract insects.

Finally, let's visit the PBS web site Scientific American Frontiers.

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