Boundaries
by Jack Nisbet

Jack Nisbet is the author of The Mapmaker's Eye, Sources of the River, Purple Flat Top, Singing Grass, Burning Sage and Visible Bones. His newest, The Collector, is due out in October.

Endless Thread
November 2007

A close friend of mine passed away last year. She really liked plants, and each fall we used to travel up into the mountains above the Pend Oreille Valley to revisit some of her favorite places. We would poke around Bunchgrass Meadows to check out the purple stems of beargrass, or muck through a muddy spring searching for a medicinal plant that smelled like celery. She was especially fond of North Baldy, where we could look way down on Priest Lake to the east, and way down on the Pend Oreille River to the west. The juniper up there smelled especially strong to her.

This year, after the rains finally came, I scrambled around North Baldy's craggy rocks to find a sprig of juniper loaded with berries that I thought she might have liked. I carried the prickly twig down to the cemetery and laid it on the her grave. At the top of the flat granite marker, my friend's family had stood up a line of flat rocks that set the headstone off nicely. Between the vertical slate and the horizontal granite there was a gap just large enough for a spider to insert some sticky webbing.

This remarkable web began with many fine spokes laid out in the rough shape of a wheel, and the hub of the wheel took the form of a carefully constructed tube that disappeared into the gap between the stones. Its fine white silk recalled one of those fingertip protectors of surgical gauze, soft and pliable. The tube web was the kind of natural wonder that my friend would have taken great pleasure in seeing.

The spider lurking within that tube, barely visible when I peered inside, was the Ariadna spider, Ariadna bicolor. These spiders are small enough -- less than half and inch long for the males, a third again larger for the females -- that they would never be noticed except for their distinctive webs. Like all spiders, though, they sport beautiful colors and proportions. The head and upper body carry the brown of fine loam, and the thorax behind is shaped and colored like a pale eggplant. Three of the four pairs of legs face forward; they bristle with tiny hairs like juniper twigs, and end in three gripping claws.

All the members of Ariadna's larger spider family have six eyes, but can't see very keenly, so they must rely on tricks to capture their prey. Ariadnas employ their ingenious webs so successfully that they can be found almost anywhere in temperate North America. Each one of their long slender tubes extends into a suitable crack, protecting the host spider from most predators. The webbing around the outside gathers at the top like a silken collar, and two dozen or more single threads radiate away from the collar as exploring tendrils. These threads do not lie flat on the ground, but ride atop silk pillars laid down by the weaver -- a circle of them around the hub, then more strategically placed supports along the length of each thread. The suspended threads act like strings of a finely tuned instrument: the slightest touch plays a note that is carried to the center of the web, where Ariadna can sense it.

When hunting, the host spider positions itself at the top of its tube, with its three forward pairs of legs perched over the top of the collar. The moment some unsuspecting prey such as a fly, ant, or gnat plucks one of the pillar-supported threads, Ariadna explodes from its lair like a jack-in-the-box, directed to the exact spot by the musical tones. With laser swiftness the spider seizes its prey with those three-clawed fingertips, then dashes back to stuff it down the tube. Even if the prey turns out to be a wasp that is much longer and heavier than the Ariadna, the tube constricts the victim's movements until the spider can deliver a death blow in the form of a poisonous bite.

During the Ariadna's breeding cycle, their web assumes a completely different role. At that time the female removes all the radiating trap lines from around the periphery of the tube, then lays around fifteen eggs directly into its mesh. The large eggs cling together in a mass, but are not enclosed in a sac like the ones constructed by many other familiar spiders -- for Ariandas, the tube itself serves as the protective sac. If a chance rainstorm floods the crack, the tube can also serve as a diving bell -- even completely immersed in water, young Ariadna spiders inside their tube have been known to survive for ten days or more.

Of course, there's a story behind the spider's evocative name. Ariadne was the daughter of Minos, king of Crete. Her mother Pasiphae also gave birth to the dreaded Minotaur, half-bull and half-human.

During that time, the marvelous inventor Daedalus worked in the court of Minos -- in fact, Daedalus had already fashioned a magical dance floor in Crete that displayed many of the resonant qualities of a spider's web. Under Minos's orders, Daedalus designed and constructed a huge labyrinth where the Minotaur could safely roam.

Crete was a powerful nation, and the city of Athens sent tribute to King Minos each year. Part of that tribute included children who would be released into the labyrinth as a ritual sacrifice to the Minotaur. The hero Theseus volunteered to be one of the victims in the hopes that he could defeat the monster, and sailed to Crete. He arrived there under the protection of Athena herself.

It was Ariadne who prepared the newcomers to enter the labyrinth, and as soon as she saw Theseus she decided to help him. It was she who provided Theseus with an endless ball of thread that he could unwind as he worked through the maze on his way to a final duel with the Minotaur. After defeating the monster, Theseus simply followed the thread to freedom.

There's more to the story, of course -- there always is with Greek myths, and with the life history of living things. As I laid the sprig of juniper on my friend's headstone, the Ariadna spider's threads radiated away from the crack like a parquet dance floor, promising twists and turns that stretched on forever. They seemed to head in every possible direction, and, at least for the moment, there seemed to be a lot of different ways to trace them out.

Illustration by Emily Nisbet.

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