Tuesday, October 2, 2012


Golden Silk Orbweaver
By the time fall rolls around in Gainesville each year, the Golden Silk Orbweaver spiders (Nephila clavipes) (aka Banana Spiders) have grown into their full glory. They first appear in early summer, small and yellow, and tend to weave their webs in low areas, across paths and near doors. But as their webs are disturbed they move higher or tuck themselves into more protected paths. If you look up into the utility lines, you can see web after web of smart spiders taking advantage of the convenient distance between the wires. The spiders that don't get gobbled up by hungry birds can get huge. These majestic creatures can achieve a leg-span of 4-5 inches. Their webs are wondrous as well. They can also be huge--several feet across. The spider silk is golden, as their name implies, and is very strong.
Golden Silk
If you walk into one of the webs you can feel the strength of the strands. The webs have as much tensile strength as steel. Scientists noticed this and have tried to use Nephila silk to make stronger, lighter parachute straps, bullet proof vests, and other materials that need to be strong. Fishermen in Malaysia and Indonesia use webs from a related Nephila spider, wrapped around a branch, to catch fish. People have even used the silk to make glorious golden cloth. Here's a link to an incredible video about creating a cape from spider silk.

This spider set up a web under our living room window. The web is about 4 feet across, stretched between a tree and a bush. It is tucked out of the way of foot traffic, but will catch the insects drawn to the lights of the house.
House Spider
Looking closer at the web, I realized that at least 12 Orchard Orbweaver Spiders had used the strong strands of the web as supports for their own. Unlike web parasites, small spiders that live in a large spider's web and steal the insects that are caught on the periphery, this arrangement is more like camp ground. They catch their own food. Except that I can't see what's in it for the Orbweaver.

One of the "Campers"
There was another small spider in the web--the male. Male Golden Silk Orbweavers are comically small. People mistake them for baby spiders. They stay close, but not too close to the female, and hope to mate without getting eaten.
Male (upper left) and Female
When they do mate, the female will spin an egg sac. The spiderlings will overwinter in the egg sac and emerge in the spring. The big spiders usually die when the temperatures get too cold. Sometimes in the early winter I will find a wilted spider hanging limply from its web, only to see it revived when the day warms up. One year, a spider set itself up next to our front porch light and managed to stay warm enough from the heat of the light to last 2 full seasons. We knew it was the same spider because it was missing a leg.

When we first moved to Florida, I found the Golden Silk Orbweavers scary and intimidating, because of their huge size, and the sticky strong webs that I often found myself tangled in. But I quickly learned how to avoid the webs and love the spiders. They bite, but are not especially toxic or harmful to people (they say the bite is similar to a bee sting). I've never been bitten, which says something about their disposition--everything bites me. I also know now that they are very beneficial because of the numbers of insects they trap in their webs. I no longer fear them, but look forward to their return each year. And each fall I revel in their golden beauty.
Golden Silk Orbweaver abdomen, detail

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