Friday, August 03, 2007

A Garden Spider

To walk out on the crumbling back porch and find that, overnight, a spider has created a huge triangular web anchored to one of the uprights and the roof, is an interesting shock.

It hit me in stages. First, the sheer beauty of the geometry, its symmetry heightened by the droplets of dew which catch the rising sun and sparkle like the hat of Kipling's Parsee, "with more than Oriental splendor." Then, an instant later I was stunned by the size. The main line forming the hypotenuse of the right-triangular construction supporting the orb was nearly four feet long. The orb itself seemed well over two feet in diameter, larger than any web I had previously seen in my yard. A zigzag of bright white silk was scrawled across the center.

The lady was hard to find. but I finally tracked her down in the shadows working on something on the edge of the web. She seemed to be re-anchoring one of the spokes.

With a magnifying glass to aid my old eyes, I saw that my new tenant was large, her body over an inch long, with yellow and black markings on her body and bands on her legs. I don't know a lot about spiders, so I had to refer to my field guides. She was a Black and Yellow Garden Spider, Argiope aurantia, and as I suspected her web was an anomaly, much larger than the usual. No-one knows the purpose of the white zigzag in the middle, called a stabilimentum, though some think that it might be camouflage, but its presence gives this spider one of its common names, "the writing spider".

She was a beauty, and her web an adornment to the porch. I decided to give her a housewarming gift. I remembered that there was a half-dead fly on the kitchen windowsill so I retrieved it with some tweezers. It buzzed fitfully but did not have the energy to escape. Being careful not to damage the web, I placed the fly on one of the sticky strands of the spiral. My hand shook a bit and the spider sensed a threat and curled up nearly invisible in the crack of an upright. After a few moments she unfolded sensing the buzzing of the fly through the tremors in the web and slowly made her way out to investigate.

She paused near it (I can't help but think, a little disdainfully) then moved in to kill and wrap it. Over the next few days she captured a wasp, a few dragonflies and a bumblebee. Sometimes I saw her sitting in the middle of the web and shaking it.

One day I noticed a somewhat pitiful little zigzag structure with a smaller spider in it at the point of one of the triangles. It seemed to use a portion of the garden spider's web as supports. I went back to the field guide to find that it was the male of her species.

I considered giving him a welcome gift, but when a slight breeze tweaked the web, he dove off the web trailing a silk line like a kind of arachnid bungee jumper. I decided that he was too skittish and I didn't want to give him the spider equivalent of a heart attack.

The following week I was walking past the porch and saw the female sitting in the middle of the orb. Thinking that she must have caught something I went to investigate ... but there was no prey. I wondered what she was doing. Suddenly she moved and a small dark blur streaked across the web. When it came to rest, I saw that it was the male.

I brought a stool out from the kitchen so I could sit with a good view to enjoy some hot spider sex.

Slowly the male retraced his steps. He was plucking at the web, perhaps to signal that he was not prey. When he climbed onto her it was impossible to see him against her coloring, but I didn't want to get the magnifying glass or get too close. I was afraid that even my breath might disturb them.

She moved again, and again the male made a dash for safety. At least a dozen times I watched the same scenario. Once, after a particularly sudden movement on her part, the male just dropped to safety on his silk line.

Finally I saw him move slowly away from her, retreating slowly up her web towards his own. Like a flash she turned, and bit, then, not even bothering to wrap him, sat and quietly fed.

Some days later I noticed three egg sacs suspended near the middle of the orb. They were a little more than a half inch in diameter.

My references tell me that she did this at night. She made a sheet from her silk, laid the eggs on it, then tucked them in under another sheet. She covered them further with a protective blanket of brown silk and formed the whole thing into a small ball. Each sac, according to my sources, contains as many as a thousand eggs. I'm sorry that I didn't see it.

A few days later there was a thunderstorm in the middle of the night with heavy wind and pelting rain. The next morning the web, the egg sacs and the spider were gone.

I looked around for a while, hoping to rescue the eggs, but they had disappeared completely.

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