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April 18, 2013 at 11:48 AM
In my last post I challenged people to identify this unusual red-fronted spider, and many readers were familiar with it.
According to Rod Crawford, the curator of arachnids at the Burke Museum, this spider is likely Dysdera crocata. It goes by one of several common names all related to its main source of prey, the woodlouse. If you’re not familiar with woodlice, you probably are by another name, pillbug, sowbug, potato bug, and armadillo bug just to name a few.
The woodlouse spider is relatively new to our area and appears to be moving north from Oregon as our local climate warms. The species is native to Europe and was introduced to North America sometime in the 19th century.
It made its way west to Portland by the 1930s but has been slower to move north. It didn’t cross the river into Vancouver until the 1980s. According to Crawford, the time it took to move north is pretty good evidence that its spread was being limited by climate.
Beyond the wagon-red color, which immediately called the spider to my attention, I noticed its long nasty chelicerae, which is a term I must admit I just learned. Before I would have called them “fangy things.”
Those fangs appear to have given the woodlouse spider a reputation for being venomous that it doesn’t really deserve. They are long and strong to puncture the exoskeleton of its main prey, but apparently the strength of bite is where the nastiness ends as far as humans are concerned. If you want to read more about it, see a clearer picture of Dysdera crocata and read about spider danger myths, Crawford has a good page devoted to it.
Crawford’s whole site on debunking spider myths is a very good source on local spider information.
I’d also like to congratulate Christina Wilsdon, who was the first Times reader to correctly identify our mystery spider. If you have a good photo of some interesting biota from our area, send it our way and it might end up here in Field Notes.
March 22, 2013 at 7:00 AM
It’s often the new or unique that stand out to us. Paired with its red head and odd shape, that was certainly the case for this spider. I found it while digging in the familiar territory of my yard garden recently and, as soon as it turned up, I knew it was something I hadn’t seen before.
The photo is a bit blurry but not for lack of trying to get a clearer one. Found at or perhaps even below the ground level while moving compost, the spider seemed very determined to get back there. Though not speedy, it seemed oblivious to my efforts to slow him (or her) down and turn it around for a clearer shot. Also it had a talent for tucking itself up into tight places to hide. By the time I could check my phone to see if I had gotten a good shot, it was gone.
Have you seen one like it before? Can you identify it?
If so, toss your answer into the comment thread or email me if you prefer. We’ll update the post later in the week with the best guess — you’d actually need a specimen for more accuracy than that — of Rod Crawford, the Curator of Arachnids at the Burke Museum.
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