I spent some time cleaning up in our yard on a recent weekend, and in the process, I ran across a good-sized spider that I didn't recognize. It had a leg span of around an inch and a half — good-sized by Pacific Northwest standards — and my ill-informed initial guess was that it was probably a harmless and beneficial wolf spider. I've been trying to get the kid interested and informed about spiders, snails, bees, yellow jackets, ants, beetles, turtles, frogs, and other animals we come across, both in terms of identification and in terms of information (don't touch this one, touch that one if you want, tell Dada if you see one of these, etc.). I showed the kid the spider, snapped a couple of pictures, explained that it was a look not touch type thing, and it eventually crept off under the fence. So far, so good, too — ever since she got over her irrational fear of bumblebees, she's been both respectful and interested in whatever creepy-crawlies we come across.
Based on my knowledge of the spiders around my home town of Portland, OR, around 200 miles south of here, I made the assumption that the most dangerous insect or arachnid in the area was the mean and aggressive yellow jacket. However, after I did some Googling and reading to figure out what kind of spider we'd found, I may need to be more careful. The hobo spider (Tegenaria agrestis) is becoming common in the Northwest and has a very nasty bite, at least anecdotally. At least one source claims that there is no strong medial evidence to support the assertions that the spider has necrotic venom, but I won't be conducting any experiments.
The unfortunate thing is that the hobo spider is indistinguishable from its otherwise harmless cousins the Common House Spider (Tegenaria domestica) and the aptly named Giant House Spider (Tegenaria duellica) other than by size or by examination under a microscope. I exchanged a couple of emails with a friendly arachnologist about the spiders, and he claimed that I'd never heard of or come across these spiders in my youth in Oregon because they were introduced in British Columbia some time ago and have only recently extended their range into Oregon.
It turns out that I've got a few of the duellica living in the yard, and they are big. They're not tarantula big, but they're at least double the size of any other species of spider that I've seen in the region. Out of curiosity, I baited some of the funnel webs around the yard with dead yellow jackets and then wiggled the web with a twig to see who came out to claim the free meal. In one case, a spider with a legspan the size of my palm and a body as thick as my pinky lumbered out, grabbed the snack, and carted it back under the window sill where his web was. I'm on the fence between making sure that the kid knows not to stick her finger in the web and relocating the spider, but I'm probably going to take the relocation option. (I'd prefer not to kill the spider; the duellica is good to have around, as it displaces and/or kills the agrestis.)
