Nature notes and photos from BC, Canada, mostly in the Lower Fraser Valley, Bella Coola, and Vancouver Island.
Tuesday, July 24, 2007
Spider watching
For the last couple of weeks, I've been pestering a spider I discovered just outside my patio door, poking my camera lens at her, aiming bright lights in her direction, and often shaking her web in the process. At first, I was just trying to get a photo, any photo; she is in a very awkward situation, up in a dark corner where, standing on tiptoe on a chair, I could barely get closer than 6 inches. And stretching like that, my hands shake. But she interested me, so I persisted. I've been taking a couple of photos every day.
She hangs in her web, a tangled mass of threads going every which direction, always upside-down. And usually with her face to the wall. Not until today, after two weeks of trying, had I managed even to see her eyes.
After a few days, she attracted a boyfriend. Ah! Spider sex! I would get a photo! So I've been checking them out several times a day, with no luck, so far. He hangs out in her web, approaching to about 2 inches, but I've never seen him closer. Not yet. (Laurie says I'm intruding on their intimate affairs; I say they don't care. They're not complaining, anyhow.)
Laurie eventually dug out a step-ladder for me. That helps; now I can get a couple of inches away, but only by breaking strands of the web, upon which she heads up, out of range. As soon as I get off my ladder, she comes back to taunt me.
Oh, the trials of a bug watcher!
Anyhow, searching through BugGuide, I found photos of the Western Black Widow that looked very similar, as to body shape and colouring. I tried again to get a look at her underbelly for the hourglass (not getting too close, just in case); she wasn't having any. I posted her photo on the ID Request page, and Eric Eaton relieved my mind; she is an American house spider, Achearanea tepidariorum. Perfectly harmless, he says.
Back to my observation post.
She is a fat spider, with a great mounded abdomen, marked in browns and blacks, with a whitish upside-down vase-shaped mark at the top. The male is tiny and skinny, about 1/4 her size, all legs and quite visible palps.
He hangs around at the edges of the web, sometimes approaching slowly, tentatively. She seems not to notice. I wondered at first if it was because she was still immature, and not interested yet, but one of the websites I consulted says that the webs of immature females are more tightly woven; hers certainly isn't.
The web seems almost too tenuous to catch anything, but last week she had a large brown moth which kept her busy for hours, sucking away at its soft parts. Another time she was eating what looked like a worm; how one would get up there, I have no idea. SpiderPharm tells me that a good part of the success in catching large prey is due to her potent venom. Oh. I'll keep my fingers away.
Yesterday she had a crane fly.
In this second photo, you can see a few of the scanty lines she uses as a trap.
And the male, tiny as he is, had moved down the wall a ways to deal with a moth ten times his size.
On a close-up (click on this for a clear view), you can see the moth scales and the silken lines that bind them.
Reading up on these spiders, I learn that males and females will inhabit the same web and mate repeatedly. So I guess she won't eat him after the first try. I may get a photo yet.
And then I'll be looking for egg sacs and spiderlings. What fun!
Update: Next post about these spiders: Fresh Laid Eggs!
I found a couple of excellent photos here and here. Somebody has excellent cameras!
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