Walking on a pier recently in Cedar Key, Florida, my daughter Amy and I spotted a large spider web stretched over the handrails. A banana spider the size of my hand sat in the middle. I handed Amy my camera. Not until I transferred the photo to my computer at home did I appreciate the spider’s creation. Now I’ll think twice before damaging a spider web.
Banana spiders (Nephila) choose locations for their webs where flying insects are likely to get caught. The web is well planned. First, the spider spins non-sticky silk as a framework. Then she fills in the gaps with sticky threads to trap her prey. Once a wasp or other insect is caught, the spider quickly wraps it in a silk cocoon. When the package is complete, she takes it to the center of the web where it waits until she’s hungry. Mostly she catches mosquitoes, flies, wasps, bees, butterflies, moths and grasshoppers. To watch a banana spider trap a wasp, click this link: Banana spider at work
Parts of the spider’s web may look haphazard, decorated with plant bits and dead insects, but the debris serves a purpose. When an insect lands in the web, the whole structure vibrates, including the extra bits—letting the banana spider know that dinner is served. The debris also shields the rest of the web from windblown leaves. As a bonus, it keeps birds from flying into the web looking for a banana spider to eat.
When an enemy comes near, the spider sets up a vibrating motion in the web to scare the trespasser away. If that doesn’t work, she uses the web’s pulsating vibration to help her jump to safety. Or she runs to a single escape strand she’s placed in the web that leads to nearby bushes or grass where she can hide..
Because the spider’s web loses its sticky quality over time, she must repair it often. Her building materials are sturdy. The silk spun by the banana spider is stronger than Kevlar, a material used to make bulletproof vests. It has a tensile strength six times that of steel.
Many people think that this large, brightly colored spider is dangerous. It’s not. Like most spiders, the banana spider is shy. People get bitten only if they hold or pinch it. While the bite hurts, it’s much less severe than a bee sting and the discomfort goes away quickly. The main symptoms are redness and blistering around the bite, and these are gone in less than 24 hours. However, people with asthma may have an allergic reaction that involves breathing problems. The bite can also cause muscle cramps.
The banana spider is more a friend than a pest, with her ability to trap and eat biting insects. The next time you see a banana spider sitting in a large web filled with dead mosquitoes, flies and wasps, you may appreciate what she’s done for you.
Banana spiders are valued by the fishermen along the coasts of the Indian Ocean, who use their webs daily. They shape a banana spider’s web into a ball and throw it in the water, where it unfolds and captures bait fish.
At one time, people hoped to use the spider’s silk to make cloth. Nothing much came of this, although the American Museum of Natural History has an exhibit of shimmering golden cloth woven from the webs of over one million female banana spiders. The silk was collected and the fabric woven in Madagascar. The spiders were released after their work was done.
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