The fall spider season has become very busy in our area, with probably more spiders, bigger spiders and a great many more calls and e-mails from concerned homeowners in the past week.
There is cause for concern, because many of those described to us have been aggressive house spiders, the so-called "hobo" spiders that have been increasing in numbers around here.
Nearly every call we have fielded in the past week involved the large black-and-yellow garden spider or one of the three Tegenaria species, the house spiders.
The fat garden spiders you're finding in among your flowers and vegetable plants almost everywhere are rather fearsome to look at, but are essentially harmless. The may be up to 1½ inches long or possibly more, and are found on a typical radiating web between outdoor plants.
Garden spiders are dark in color with a definitive yellow pattern on the back of their lower body and a few yellow streaks along the abdomen.
All spider bites are venomous to some degree, but the garden spiders are reluctant to bite unless terribly provoked, and even then they aren't apt to inject much venom. They are about as peaceful as any spider you might meet, and bites are almost always accidental.
When you see one of these rascals in the garden, try to leave it alone and give it some room; it does a great service by ridding your garden of more destructive insect pests.
The house spiders are another story altogether. Of the three that are now common to the Lewis County area, the aggressive house spider is perhaps our most dangerous arachnid.
The aggressive house spider, Tegenaria agrestis, first arrived in Washington at Seattle in about 1930. A native of Western Europe, this toxic hitchhiker came in a shipload of agricultural commodities and didn't make much of a splash until the middle 1960s, when significant numbers were noted in both eastern and western parts of the state.
These large 1½ inch (plus!) spiders are mostly a variable dark brown with a little lighter brown mottling on the lower part of their body. The legs are long and somewhat hairy, and they are fierce-looking animals, indeed. Their ferocity, unfortunately, is more than skin deep!
You are most apt to find one of these spiders in your sink or bathtub in early fall, when the males range far and wide in search of mates. They live in a distinctive "tunnel web" in dry crawl spaces around the house or more often in woodpiles and stacks of unused, old lumber in the yard. They enter the house during the search for a suitable female.
The two relatively non-dangerous subspecies, the common and the giant house spiders, aren't much of a threat to humans. Unfortunately, it takes a pretty seasoned entomologist to tell the difference between them and the aggressive "hobo" spider.
The hobo will bite with little or no provocation. All you need to do is accidentally get in immediate proximity to one and you could get a painful and dangerous bite. Many such bites occur when someone is carrying in firewood or cleaning up woody waste around the place. Gloves are advised whenever handling such material in the fall.
The initial bite is described as nearly painless, but within half an hour it develops a white center, reddening around the wound, and some pain and itching. An hour later, the victim will begin to feel nauseous or dizzy and will experience growing headaches. Seek immediate medical attention if you think you have such a bite.
For years, we have heard that the bite of a hobo spider isn't fatal in the Northwest, but that is no longer the case. A young woman near Spokane died last year as the result of a hobo spider bite, after delaying her search for treatment for several weeks after she was bitten.
Be aware that you may possibly have aggressive house spiders around, keep watch for the telltale tunnel webs, and take all possible precautions when working in an area where the big spiders may be. Alertness and awareness are our best defenses against autumn house spiders.
Russ Mohney, who describes himself as a "peasant naturalist," is a fourth-generation Lewis County outdoorsman. He has published several books and many articles nationally, and continues to write on a variety of outdoor recreation subjects. He can be reached by e-mail at russm@localaccess.com or at P.O. Box 580, Centralia, WA 98531.
