The spider struggle continues

13 days until classes begin, and this last batch of spiders are now about 13 days old. I took a few pictures (I stashed one on Patreon and Instagram) and had to struggle a bit with the photomicrography system, which I’ve mostly neglected this summer, on top of struggling with putting a lab demo together on video. Tomorrow is going to be busy feeding a few hundred spiders…well, maybe. Another thing I’ve noticed is that some of the babies have died, just out of natural mortality, I think, and tomorrow will involve counting the living and the dead, hoping the former outnumbers the latter.

Somewhere in here I’ve got to get my syllabi order, too.

Mighty Huntress

I learned something today! There is this spider I keep on my office desk. I’ve always wondered, since these spiders are so passive and patient, and I’m feeding them wingless Drosophila, do they just wait until one stumbles into their web, or do they ever actively hunt? The answer is…they’ll hunt when opportunity arises.

So this spider has webs strung across this wooden frame, and she tends to hang out near the top of one of the sticks.

This afternoon I watched her abruptly descend on a drag line from her perch to the gravelly scree directly below to drop on a fruit fly walking by, bite to kill, and wrap it in silk before hauling it right back to her starting point. It was spectacular!

In case you’re squeamish about this sort of thing, I’ve put a closeup of the proud hunter below the fold.

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Everyone needs a pet spider!

If there’s just one thing I miss from my zebrafish days, it’s being surrounded by fish tanks. Lovely burbling fish tanks, filled with little dancing fish, so soothing. So nice. So restful.

Well, they’re gone now, so I wanted something to replace them, so I threw together a couple of terraria with spiders. It was easy. First I thought of repurposing all these fish tanks I’ve got, but they’re too large — my spiders are small, these aren’t tarantulas — and the lids were perforated and wouldn’t be any kind of obstacle. Then I found these acrylic display boxes, which are intended for 1/32 scale model cars, or dolls, or action figures. I can do better than that — spiders! So I made a few.

The one on the left holds a bronze jumping spider and a chunk of stick, while the one on the right is Parasteatoda with a simple frame I slapped together with coffee stirring sticks and hot glue. The jumper has its own charm, but is a little on the small side right now (I’ll fatten him up). The house spider is fascinating and is a real distraction in my office. She immediately started assembling a web on the frame, scurrying about, jumping from stick to stick. I really recommend them for everyone’s office. You should get one or two or four.

I also needed some distraction. Oh no! Another egg sac erupted with babies!

I’m not sure what I’m going to do. My incubators are full to capacity. I might have to try feeding them en masse, until they’re big enough to thrive, and then turn them all loose somewhere. Like my house. Mary won’t mind.

Alternatively, you could all buy some of those acrylic display boxes, stop by the university, and I could stock them up for you. Seriously! They’re fascinating! Like aquarium fish, only dryer!


In case you have no idea what you’re looking at in that last picture, here’s a key.

Hope that helps!

Spider feeding day!

It’s been a long day of preparing my mighty army of baby spiders. All have now had flies sacrificed to them, so while I was flicking flies into vials, I recorded and uploaded this short clip of one Parasteatoda happily finishing off her prey.

They are so young, and yet they’re already murderous hellbeasts. At least from the perspective of Drosophila.

Spiders of the Industrial Wasteland

Today I had to take the car in to get new tires. We’re a rural bit of the country, but that doesn’t mean we’re all green and soil and fresh sprouts — this was a tire store next to the railroad tracks with a line of grain elevators across the street. I wasn’t about to hang around in the waiting room, so I went prowling about the industrial wasteland next door.
What did I find? Cryptic machinery, corrugated sheet metal buildings, and iron rails, of course. With spiders!

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Dispelling the aura of danger around spiders

I keep telling everybody — spiders aren’t as scary/dangerous as you think. Now I have a paper that quantifies the risk of deadly spider venom. It’s low.

• The increasing popularity of pet arachnids urges some governments to take protective steps to prevent serious envenomations.

• A literature review was carried out to assess which arachnids can be classified as potentially dangerous.

• About 0.5% of all spider and 23% of all scorpion species were classified as potentially dangerous.

• Even envenomations from the most dangerous arachnids have a low percentage of serious or even fatal consequences.

• We conclude that the public threat from pet arachnid envenomations has been overrated.

Here’s the list of potentially dangerous genera.

Note that the list errs strongly on the side of caution. It lists Eratigena, the hobo spider, but says in the text that “there is not a single verified bite that confirms E.agrestis or other members of this genus as dangerous to humans”. Latrodectus, black widow spiders, do have a real record — 23,000 incidents reported over 8 years — but less than half of those cases involved envenomation, and only about 1% exhibited severe effects, and there were 0 deaths. The Parasteatoda and Steatoda species I work on are only briefly mentioned and dismissed because their effects are much weaker than those of Latrodectus.

I’ve also never encountered any of the spiders they list, and I’ve been looking. I guess if I lived in Malaysia or Brazil I’d experience more of the thrill of danger, but here in Minnesota we’ve got a non-existent concern, and even in those tropical countries it’s a relatively minor worry.

(Of course I learned about this paper from Gwen Pearson. It’ll be useful if anyone at the university expresses concern about the hundreds of spiders currently in my lab.)

’tis the season

My spider family is going mad, spewing baby spiderlings everywhere. I came into the lab today just to maintain and feed the several hundred hatchlings I’d acquired over the past few days, and what do I find? Another egg sac has opened up, and another hundred or more babies are begging for attention.

Yeah, yeah, I was a responsible parent, and I separated out as many as I could and put them into nice clean vials. I’m reaching capacity, though. This means I have about 300+, maybe as many as 400, itty bitty Parasteatoda offspring in my lab, packed into two incubators. Looking ahead optimistically, I can maybe accommodate 60 adults in the lab, if I pair up males and females. It feels weird to say it, but I’m good if I have 80% mortality in the babes.

I suppose if they thrive I can just turn the majority loose in my basement.

Hungry hungry spiders

All these baby spiders hatched out over the last few days, and I had to start feeding them. I’ve got a lot of flies, I opened each vial one by one, and tossed in a surprised wingless fly. All the babies, even though they’re only two days old, had strung silken lines all over the place — baby’s first death trap! — and were waiting patiently, hanging upside down like the grown ups, and wow, were they ever excited when the first fly was snared!

Here’s a pair of Parasteatoda juveniles, literally seconds after I put a single fly in. They descended on it immediately. Baby’s first kill!

I’m about halfway through the feeding. It’s starting to go faster as I get better at manipulating massive numbers of flies. The Runestone line is all completely fed now, with the corpses of their twitching prey piling up. I think I’ll take a break and feed the remainder tomorrow.