You can learn a lot by looking at spiders and their webs

Published 12:00 am Tuesday, October 14, 2008

By Melody Bell Wilkes
For the Salisbury Post
Take a look at the countryside this time of year and you can spot some magnificent spiders.
Many are making their webs, finding partners and laying eggs for next year’s generation. Common in wooded and garden areas are jumping spiders, wolf spiders, funnel weavers and the orb weavers.
Contrary to popular belief, spiders are not insects. They are classified as arachnids like ticks, mites and scorpions. Spiders have eight legs; insects have six. They also have two body parts, the cephlathorax (head and thorax combined) and abdomen. An insect has three body parts, a head, thorax and abdomen.
Most insects have wings and antennae. Spiders do not. Their legs are covered with hairs that serve as sense organs.
Scientists believe there may be as many as 50,000 to 100,000 kinds of spiders.
Spiders inject venom into their prey, and juices from the digestive glands liquefy prey before it is sucked into the mouth by the stomach’s pumping action. The empty shell of the insect is discarded after feeding.
If provoked, a spider may bite. But only two dangerous species live here: the black widow and the brown recluse. A bite from either will need immediate medical attention.
Some smaller spiders are among the 2,800 species of colorful jumping spiders. They don’t build webs and have larger eyes for seeing prey up to 4 to 8 inches away. They are daytime hunters and walk with an irregular gait with the fourth pair of legs modified for jumping.
If an insect is in sight, they pounce, but not before securing a silk thread as a safety line in case it misses its mark.
At first glance, the wolf spider is a large impressive spider. You might even think you saw a tarantula, which is of the same genus. About 2,000 of the species live here. The largest is called the Carolina Wolf Spider and can grow up to 1.5 inches long.
Common spiders are primarily nocturnal, but you may see them during the day. Some hide under objects, some dig short tunnels and others dig burrows. The female attaches her large egg sac to her spinnerets. As the young spiderlings emerge, they climb onto the mother, who carries them on her back and brushes them away from her eyes. If any of the spiderlings fall off, they climb back on the mother’s legs again.
Roughly 500 species of funnel weavers are easily recognizable in the morning dew. Funnel weavers can be found on the ground or along bush margins where insects cross. The spider hides at the narrow end of a funnel that spreads out across the grass. Feeling the vibration of an insect crossing the web, the spider dashes out to carry it back to the funnel
Orb weavers build the most intricate webs in open areas, between tree branches or bushes. Some refer to the black and gold orb weaver as the “writing spider” because of the zigzag pattern that adorns the center of the web.
The spider’s web is made from silk and is designed to trap its food. Spider silk is fibrous protein made from silk glands found in the abdomen. Silk hardens not by contact with air but by mechanical stretching. The spider uses its legs to draw out the silk through small tubes, called spinnerets, found at the base of the abdomen.
Spider silk cannot be dissolved in water and is the strongest natural fiber known. Scientists are using biotechnology to try and find a way to mass produce such silk. Among the uses of the silk are military applications in parachutes and flak jackets, textiles, packages, ropes, sailboat masts and naturally biodegradable nontoxic sutures.
A small pocket field guide can help if you’re looking at different types of spiders. I recommend the Golden Guidebook called Spiders and Their Kin by Western Publishing Co.
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Melody Wilkes is owner of A Walk in the Woods, an environmental education company that provides outreach wildlife programs. Contact her at 704-436-9048 or visit