Monday, January 14, 2008

Silk


Our resident spider, a female Argiope argentata, as big as a toddler's hand, persists in building her orb between the screen porch and the white torch tree, across a path we are used to traveling. Which means, at our forgetful age, that we occasionally blunder into the web and end up with Argi clinging to our clothes. We brush her off onto the ground, and the next morning she once again hangs in her usual place, her splendid web more glorious than ever, three kinds of silk spun against the sky.

Fossil spiders with spinnerets (silk glands) on their abdomens are known from the Devonian and Carboniferous periods of Earth history, 300 to 400 million years ago. A 110 million-year-old piece of Spanish amber clearly shows a fly and a mite trapped by strands of spider silk, apparently from a spiral web. This possible instance of orb architecture coincides in the geological record with the explosive diversification of flowering plants and pollinating insects. "What refinement of art for a mess of flies!" exclaimed the great entomologist J. Henri Fabre, in his The Life of the Spider. "Nowhere, in the whole animal kingdom, has the need to eat inspired a more cunning industry."

And ponder this. Hatchling spiders spin webs that rival the finest work of adults. Says Fabre: "There are no masters or apprentices in their guild; all know their craft from the moment that the first thread is laid." Somehow, the Calatravan gift of cable architecture is encoded in their genes, in a four-letter code they share with you and me. The DNA spins proteins with the same facility the spider spins silk. And somehow these two things are linked.

I suppose we should move the spider to another location where it won't impede our passage. I like it where it is. I can sit in the hammock chair on the porch and see it suspended just beyond the screen, a reminder of how much we have learned about the world -- and how much we have yet to learn.