Hobo Spiders, Part 1 of 4

(The Book of Deadly Animals is now available in the US. I’m going to celebrate by running here an expanded version of a story from the book.)


January, 1988. A 56-year-old woman from Spokane felt something bite her on the thigh. She came down with a migraine-style headache and nausea. Her thinking became addled. In the coming days, a patch of dead tissue sloughed from the spot where she'd been bitten. It was perhaps two weeks before she sought help, and by then it was too late. She was bleeding from the orifices, even from the ears. Doctors found her blood deficient in several basic components. Her marrow had stopped making red blood cells. Having lingered in the hospital for several weeks, the woman died of internal bleeding.

There were other cases.

November, 1995. In a suburb of Portland, Oregon, a ten-year-old boy woke with a pair of bites on his leg. The wounds swelled, grew hot, blistered. Dead tissue dropped away. A week after the bites, his leg was swollen and red. He suffered fever, nausea, and debilitating headaches. After a month, the pain of the wounds was mostly gone, but a bruise-like patch of blue remained on his leg. The headaches lasted four months. 

October, 1992. A 42-year old woman from Bingham County, Idaho, felt the burning bite of a spider on her ankle. She, too, came down with a headache and nausea, as well as dizziness. The bite blistered and burst, leaving an open wound that continued to grow. After ten weeks the crater was big enough to accommodate two thumbs and ringed with black flesh; it was still growing. Eventually, more than two years after the bite, the wound had healed into a sizable scar, beneath which the veins were clotted. The woman's ability to walk and stand remained impaired, limiting her job options.

The spider she had found crushed within her clothing was a hobo spider, Tegenaria agrestis, a member of the family Agelinidae.


*


The Agelinidae are hairy, brown or gray, often big enough to straddle the face of a pocket watch. They build flat webs with a sort of billiard pocket at one corner in which the spider lies at her ease to await prey. They're common as cliches, found in temperate places all over the world, in about 38 genera and 500 species. In England a type of agelinid, the lesser house spider (Tegenaria domestica), is found behind books on the shelf, its thick web tearing when a volume is consulted. In the American Southwest I've often seen a gray agelinid with long black stripes. Its abdomen is typically an ovoid tight and ripe as a September plum. This species has eyes that shine like scattered emeralds in the dark, and its webs lie about on the ground cover like silk handkerchiefs—crisply white at first, but progressively dirtier with time and use. I have seen these spiders rush out of the funnel when an insect lands on the handkerchief. The spider closes on its victim like a hirsute hand. It delivers what looks incongruously like a kiss to the prey's head, whereupon the prey ceases to struggle with shocking suddenness.

Soon the spider drags his prey into the funnel, where it is hard for a nosy biped to watch. Usually all I can see are dark masses and an occasional shadowy scrabbling of legs. What happens, of course, is that the spider injects its digesting venom into the prey, breaking its innards into soup before sucking them down. The next day I often find a few insect legs littering the edge of the handkerchief. 

Parker Grice

In the upper Midwest, where the outdoors is coldly inhospitable to spiders several months a year, I have often noted another species of agelinid residing in basements. Anything left on the basement floor undisturbed long enough is likely to harbor a mass like a frayed handful of cotton balls. In one such web I noticed a hummock shaped like a human grave formed over the body of some black creature. This carcass was apparently too much trouble to drag over the web’s edge. The spider had simply built over it. These northern agelinids are brown and rapid. I've found in their webs creatures as diverse as millipedes and mosquitoes. I touched one web, delicately as I could, and saw the spider heave itself out of its funnel-shaped retreat and immediately collapse back into it, so fast I could hardly have told what it was if I hadn't already known. It reminded me of horror stories told by arachnophobes, about spiders emerging from bathtub drains. I withdrew my finger with considerable haste.

The web felt like cloth made of human hair. It didn't stick to me. This is typical of the agelinidae, including the hobo spider—their webs aren't gluey, but depend on their deceptive surface to snare insects. What seems a solid, smooth place to land is actually a layered network of filaments. Most insects lack the foot-gear to negotiate this snare. Their feet fall between the strands, their claws snagging and delaying their escape long enough for the spider to seize them. The spider itself walks on the strands by clasping them between claws that oppose each other, much like the opposable thumb-and-finger arrangement of a primate.

The hobo spider shares the web style and habits of these kinsmen. It is clad in brown herringbone and its body is typically just short enough to fit on a Lincoln penny. Its genus name means mat-weaver; the species name suggests the agrarian lifestyle the species leads in Europe. But in North America the hobo spider has taken up an urban lifestyle and made its presence known to the human community in ways its European experience never suggested.
Next: Myths and Fears

3 comments:

  1. Gordon- interesting article. We've seen a pretty large influx of these spiders in the last few years. I noticed them at our first house after we bought a pickup load of cypress and cedar mulch. They are FAST. They build the funnels/pockets, and they seem to run along the edges of anything tall enough to hide behind. I'm always amazed at their speed and their size!

    Enjoyed the article.

    Russ Tidwell
    Garden City KS

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  2. Very interesting.. and thanks for sharing these informative but tragic stories of hobo spider bite victims. Although some people and references say that hobo spiders are not really dangerous, we should still be careful not to be bitten by these creatures. Yes, it's not yet proven if they're venomous or not. But the bacteria (or whatever you might want to call that) that pass from their mouths can cause serious problems to our body. Source: hobospiders.net

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