Spider identification agonies. Species are lies.

Spider taxonomy drives me cross-eyed. Today I was working on sorting egg sacs, tearing them away from their mommies, who don’t like that one bit — they’re very protective. I’m learning to tell the different species apart without a microscope. For instance, Steatoda triangulosa has a distinctive zig-zag of pigment on their abdomen that looks like a row of triangles from above, and they also have nearly spherical egg sacs that are white, have a fluffy surface, and are often semi-transparent. Parasteatoda, on the other hand, has an irregular mottling that sometimes looks roughly stripey, and their egg sacs are football-shaped, beige, and have an opaque leathery/papery surface (there are two species of Parasteatoda around here, P. tepidariorum and P. tabulata, which I haven’t learned to distinguish — it requires careful scrutiny of their genitalia — and my live spiders refuse to sit still long enough to poke around their private parts). Those are my rules, they’re what helps me figure out who is what.

So today I’m parting Lyanna from her egg sac…here’s Lyanna:

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Disgusting

The Mirror has an article on a man who claims to have been so severely bitten by spiders that he can’t work. You probably don’t want to read it: it’s mainly lots of close-up, full-color photos of oozing, infected wounds full of pus, and it’s going to horrify and sicken most people. There is one photo of a large false widow, but there is no connection between it and the person’s injuries, and I have to suspect something else is going on here.

The man and his son have multiple lesions all over their legs…how? These are solitary spiders, mostly, and they have no interest in biting people. One bite, I could believe; if you rolled over in bed on one, crushing it, it might bite in self-defense. But numerous bites? This makes no sense. Ticks, bedbugs, that sort of nasty beastie that actually feeds on humans, I could see, especially since those kinds of bites are recurrent and prone to infection.

This is not the first time I’ve seen the UK tabloids freaking out about spider invasions. What’s going on over there? Is this a symptom of rising xenophobia? Can I expect US tabloids to start inventing lurid stories of evil spiders killing people in their beds?

Gilly’s breakfast

I know what you’re all saying: I haven’t been posting as many spider photos lately. Guilty as charged. In my defense, classes have started up, and I’m busier, and I’ve already got grading to do, and I’ve got all these students, and…

OK, you don’t want to hear about it. So this morning I fed a few of the spiders and tried to get some action shots.

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Friday Spider

I knew who I was cheering for — my spiders are combfoots, too, and the behavior I see in this video is exactly what I see in my colony. The careful guarding of egg sacs, the swift wrapping of prey, that disabling bite once the target was helpless is exactly what I was watching in the lab this morning. Very cool.

We also got several new egg sacs this morning. I’m feeling a bit overwhelmed, paternally. Anyone want pet spiders around here?

(The answer is no. Well, I’m just going to have to drop them off in their forever homes without the knowledge of their new parents.)

Science, why you gotta do me like this?

“It would be cool to map the appearance of a pigment pattern,” I said. “Just photograph spider abdomens over development,” I said. “It’ll be easy,” I said. “Just do it!” I said.

So I took these Steatoda triangulosa embryos that emerged from their egg sac yesterday, and I sat down at my microscope and configured my camera to a useful and consistent setting (with a little tinkering, I found I could get decent photos at f/4, 1/80th of a second, ISO 3200 (!), at 64x on my Wild dissecting scope), lined up the containers with the spiderlings next to me, and thought I’d just march through and snap photos of the dorsal surface of the abdomen. Then I’d repeat this procedure every couple of days, and at the end of it all I’d have photographic series of pigmentation changes over time in a developing set of spiders. Simple! Except…reality intrudes.

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Steatoda triangulosa!

I said I was going to tend to my shiny newborn Steatoda triangulosa today. It didn’t take as long as I expected. Here’s the vial of my freshly emerged spiderlings; the egg sac is the foamy looking bubble at the bottom, attached to the yellow plug on the vial, and the little dots are the babies.

There were only nine spiderlings from that egg sac. It was a bit of a surprise, since when a Parasteatoda egg sac pops, I easily get over a hundred spiderlings. It makes me wonder how well S. triangulosa does in the wild — I can tell you from our summer survey that they were the rarest of the false widows we found, with even S. borealis far more numerous, and they were a distant second to Parasteatoda. Now I’m curious about what niche they fill in the local spider ecosystem.

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Chemistry and triangulosa

Work is heating up as it always does in the first few weeks of classes. Today and Friday I’m blitzing through a basic chemistry review in cell biology, because…biology is all chemistry. A very narrow and specific domain of chemistry, sure, but if you don’t understand how electrons flow you’re getting nowhere in cell biology. Yesterday was spent re-reading a lot of introductory chemistry stuff to remind me of how this all works, today I lay it all out for the students, who might be bored, but still a bunch of them will mess up on the easy chemistry questions in the first exam.

It always shocks incoming students who think biology is all frog dissections and memorizing organs. Nope, all chemistry, and in order to get the chemistry, you need to know the math. So all you high school kids thinking it would be neat to major in biology and play with spiders, buckle down and learn your basic algebra and pre-calc, at the least, and work through chemistry and physics.

Then I have some lab stuff to do. Today I’m going to focus on our Steatoda triangulosa. We’ve got a few young second generation juveniles coming up that I need to sort into larger quarters, and another egg sac that is full of baby spiders. The cool thing about S. triangulosa, besides the pretty pigment patterns, is that their egg sacs are fluffy, loosely woven silk and are semi-transparent, so you can see the eggs right through them, and right now I peek in and it’s a mass of writhing spider legs, so they’re about to emerge, I’m sure. The less cool thing about them is that they seem to be slower to develop, and for at least the one mama I’ve got in the lab, lay a smaller number of eggs. I might have to go hunt down some more adults so I have a larger sample before the frost hits.

Anyway, I’ll take pictures! I think I’ll post a purely S. triangulosa article later today.

But first, chemistry! That’s my day sorted.

Bee-killer

It begins with the screaming of the bee. We looked down into a flower patch, and there was an innocent honeybee, snared in a spiderweb, twirling maniacally and buzzing frantically as it struggled to get free. Mary told me to free it…I said “No,” callously.

I followed the lines of the web, a rather tattered orb at this point, and found what I was looking for — the claws of the predator, peeking out from under a leaf.

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Walking with spiders

I went for a walk in lovely downtown Morris today, and was rather disappointed. Tegenaria has taken over! Where earlier this summer I would have found the delicate, airy cobwebs of my favorite false black widows, there was nothing but these thick, dense sheets of webbing leading to tunnels of silk with these massive spiders lurking within.

OK, fine, they’re still spiders…but they’re far more shy than Parasteatoda. I’d gently and slowly ease my camera lens towards them, but long before the spiders were in focus they’d dart deeper into the tunnel. It was frustrating. I started seeing the utility of this probe lens.

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