Quick notes

The copyright claim on our Ark video has been resolved, in my favor. This means the money comes streaming into my pocket again! That means I have now earned (checks video analytics) … $1.74! Party time!

More significantly, and of much greater interest, the Steatoda triangulosa egg sac I’ve been nursing along has hatched! Babies have been sorted into separate containers and are flourishing in my very crowded incubator.

Their mother laid another egg sac to celebrate. I’ll be collecting baby spiders well into October, and perhaps one of her daughters will grow large enough to start contributing, too.

Growed some more

Time for my weekly spider measuring event. The young’uns molted again, and once again, they’ve grown some more.

It’s a fairly steady pattern, as I might have expected. They eat, they get bigger. There’s a fair amount of variability there, and I’ll post a couple of photos of the spider on Patreon to illustrate that.

I’ve got another egg sac close to hatching, but as usual, Steatoda triangulosa is taking its sweet time. The data so far is a rough outline with data taken at weekly intervals — it’s clear that I need to do more frequent sampling to get a better picture of how pigment patterns develop, but these guys are not in any hurry to get under my microscope. It won’t hurt, I promise!

Mundane news from the spider lab 🕷

Only a week and a half until classes come crashing down on me! Today was a lab maintenance day, next week I’m relocating to my campus office every day, to get back into the routine. So the news of the day is:

  • The latest Steatoda triangulosa egg sac has not yet hatched out. S. triangulosa is dilatory, especially compared to Parasteatoda tepidariorum. I’m pretty sure I’ll see another wave of spiderlings in the next few days.
  • The adult S tri made another egg sac, making a total of 4 more waiting in the wings. This is good news — it means I’ll be getting new spiderlings every week or two for a while.
  • A P tep egg sac also hatched out this morning. There are 100-150 baby spiders awaiting my care. Today I just threw them a bunch of flies and told them to kill something, daddy’s busy, I’ll sort them out tomorrow.
  • I realized that all of the incubators in my lab are full up. There’s a bigger one on the third floor, but that means I’m going to have to trek up and down stairs every day.
  • I fed everyone. That took a while. Even with my super efficient Fly Shaker™ it was a lot of uncorking vials, shaking flies into them, stoppering them back up, and stuffing them back into the incubator.
  • The subset of S tri I’ve set aside for weekly measurements molted again, which means with my feeding regimen they’re molting ever 20 days.
  • A couple of those S tri are getting huge, fast. May need to crank up that feeding regimen.
  • One glitch in the routine: the building diH2O tanks dried up last week. I need diH2O to make fly medium, to make flies, to feed to the spiders, and I’m on a constant treadmill of making more. An interruption in the cycle of fly-making means there may be a supply chain problem next week, a little gap in production. The spiders might get hangry.
  • I stooped to buying spring water from the grocery store (Morris tap water is not acceptable for much of anything) and got fresh fly bottles going today.
  • I reassured them that even if there is a fly problem, the students are coming back next week, so there should be a fresh supply of ripe, juicy bodies in the hallway.

That is all.

Craftin’

Busy morning. They’re only going to get busier.

One of the things I got done today was to assemble of set of my Spider🕷 Studios™️, Mk II this time, with thinner papers and small tabs of tape. As you can see, once I’ve got spiders and their webs inside, I can use the helping hands to hold the hoops in any orientation I want.

I had to get them ready today because…see the small box? What’s in the box? Not Gwyneth Paltrow’s head, although it might fit. You might see a small mottled ball in the box — that’s a Steatoda triangulosa egg sac, and the mottling is caused by the embryos maturing enough to have black legs on their pale bodies. The legs are twitching (maybe they’re dreaming?) so their emergence is imminent, and I need to promptly set up the babies so I can document pigment changes over the next few weeks.

Really, it’s all just playing with office paper, a paper cutter, and time tape. It won’t be real science until I progress to duct tape, hot glue, and cardboard.

Do spiders dream of arthropod sheep?

You ever watch a sleeping cat or dog, and see their little paddy-paws twitching and their legs all curled up? Cute, isn’t it? You can just imagine they’re dreaming.

Spiders do it, too.

Jumping spiders are special because, unlike most arthropods which have fixed eye positions — they have to turn their heads to change their field of view — they have telescope eyes which can swivel, so you can actually see their eyes move while they are presumably sleeping. This has led some investigators to suggest they have a kind of REM sleep.

Sleep and sleep-like states are present across the animal kingdom, with recent studies convincingly demonstrating sleep-like states in arthropods, nematodes, and even cnidarians. However, the existence of different sleep phases across taxa is as yet unclear. In particular, the study of rapid eye movement (REM) sleep is still largely centered on terrestrial vertebrates, particularly mammals and birds. The most salient indicator of REM sleep is the movement of eyes during this phase. Movable eyes, however, have evolved only in a limited number of lineages—an adaptation notably absent in insects and most terrestrial arthropods—restricting cross-species comparisons. Jumping spiders, however, possess movable retinal tubes to redirect gaze, and in newly emerged spiderlings, these movements can be directly observed through their temporarily translucent exoskeleton. Here, we report evidence for an REM sleep–like state in a terrestrial invertebrate: periodic bouts of retinal movements coupled with limb twitching and stereotyped leg curling behaviors during nocturnal resting in a jumping spider. Observed retinal movement bouts were consistent, including regular durations and intervals, with both increasing over the course of the night. That these characteristic REM sleep–like behaviors exist in a highly visual, long-diverged lineage further challenges our understanding of this sleep state. Comparisons across such long-diverged lineages likely hold important questions and answers about the visual brain as well as the origin, evolution, and function of REM sleep.

If this were happening in a cat or a dog we’d easily assume the behaviors were a reflection of whatever they were dreaming about. It would be nice to imagine this was just as true of spiders, but I’m going to be slightly skeptical of the idea that the behavior is indicative of “dreaming” or even analogous to REM sleep. The authors are cautious, too.

The complex visual and cognitive behaviors of salticids and their relatively small nervous system facilitate experimental tests of the role of visual experience in REM sleep–like retinal movements. Eye movement patterns during REM sleep have been hypothesized to be directly linked to the visual scene experienced while dreaming—begging the deeper question of whether jumping spiders may be experiencing visual dreams. This raises a unique opportunity to test this “scanning hypothesis” in jumping spiders, where retinal movements can be observed. Since visual input can be controlled in jumping spiders early on (unlike in humans), retinal responses to repeated visual stimuli presented during the day might partially reappear during REM sleep–like states.

The problem I have is that we don’t know all that is going on in the brains of humans during dreaming or REM sleep — so how can we compare that to what spiders experience? A deeper analysis of the activity of the nervous system would be needed to do a good comparison, and this paper is only looking at behavior.

An alternative to “dreaming”: spiders go through waves of alertness during sleep. At some levels, they are awake enough to monitor their environment, so those eye movements aren’t a consequence of dreams — that’s the spider doing sentry duty, scanning what’s around it to search for prey or threats. The movements tell us nothing about the inner life of a spider, only that it wants to eat or avoid being eaten. You know they don’t have eyelids, right? They aren’t as blind as we are while sleeping.

That doesn’t mean the behavior lacks any homology with vertebrates. Maybe our REM sleep is also a consequence of the evolution of rising and falling levels of alertness, and dreaming is just a side effect of brains randomly invoking patterned activity on top of all that.

If spiders dream, though, I do wonder what bloodthirsty scenarios are playing out in their heads. That may also be similar to vertebrate dreaming — I don’t think my cat dreams of frolicking in fields of dandelions, but of ripping the heads off smaller mammals. But that’s my psycho cat.

Another week, another data point

I’m still regularly collecting data on growth rates in Steatoda triangulosa. Here’s what it looks like on day 39 (dark red line is the mean, I’ve included data for individual spiders in a lighter color to illustrate the variation):

They’re now at about, or over, half the adult body size, and are looking fairly mature. The palps haven’t fully matured, so I can’t sex them very well, but the ones I suspect are male — they just have a bit of a bulge — are on the smaller size. The couple that have really taken off look very female to me so far.

I’m discovering all kinds of complications, though. In particular, size is definitely a function of feeding. I gave them all a mealworm earlier this week, and some of them look hugely rotund right now. Fruit flies are definitely not adequate for the full nutrition of a growing spider, so it looks like I’m going to need to spruce up the mealworm colony soon. I’ve got another S. triangulosa egg sac that has reached the stage of seething darkness, which means I’ll have more babies this week.

Also the pigmentation is distinct and strong, and now it’s obvious that these spiders have white triangles on a dark background, rather than dark stripes on a pale background. This next batch of babies are going to require daily mapping of pigment patterns so I can see exactly what’s going on. I’m about to post a few photos on the Patreon page, if you want to see.

Spider Studio Mk. I

I’ve been struggling to document pigmentation changes in my developing Steatoda triangulosa because they’re annoyingly alive. They’ve got preferences — they like to hang upside down, they will occasionally move, they are not being obliging as far as photography goes. They’re as lovely as a supermodel, but they’re also somewhat diva-ish and uncooperative. When I tell them to pose, or spread those legs, or look at the camera, they just ignore me. It also doesn’t help that I’ve got them living in these rigid containers, and if I shoo them out into a more photogenic location they get agitated and skitter about.

So I thought of a better way to manipulate them. Behold, Spider Studio Mk. I!

As usual, simple is better. All this is is a strip of paper curled into a cylinder, held together with two pieces of tape, sandwiched between the top and bottom of a petri dish. It’s ridiculously simple. The first test was to put a spider in there and see what they thought of it. They liked it! They built a cobweb in there and were hanging there, as always, when I came in this morning. Big bonus: they seem to prefer attaching silk to the paper walls than to the plastic dishes. I simply took away the petri dishes, leaving me with a nice calm undisturbed spider hanging in a paper hoop. I could orient the ring any way I wanted without stressing the spider at all!

I took a few pictures of my test subjects (I’ll put them on my Patreon for anyone who really wants to see them). It was great. I could take a picture of the dorsal side, and then flip the ring and take an equivalent picture of the ventral side.

I still have to make a few refinements. The paper ring is a bit thicker than necessary, and it still gets in the way when oriented to certain angles, so I’ll make thinner ones. I’m also going to stick some paper handles to the outside so I can use these soldering helping hands I’ve got to hold them in place.

There’s nothing I can do to cope with these being living animals. They still like to shuffle around on their web, but minimizing manipulation reduces that.

More progress!

Another week, another data point

The data collection plods on. I’ve added body length measurements for my growing Steatoda triangulosa babies, and they’re coming along nicely. What you’re seeing here is body length in mm vs days after emergence.

They molted on day 22, which accounts for the slower rate between the 2nd and 3rd timepoint — once they shed that constraining cuticle, growth rebounded nicely.

There is some variation in the individual growth rates. The smallest baby is 2.1mm long, the largest is 3.4mm. They’ve also gotten much harder to measure, because they’re more active and get more annoyed at being put under the microscope. I had to drop two of them from this week’s measurement because they wouldn’t cooperate and lie in an appropriate orientation.

I’m experimenting now with an alternative method of keeping the ones I’m recording: I made simple paper strips in a circle, sandwiched between two petri dishes. The plan is to get them to build their cobwebs in that, and then I remove the petri dishes and have the spiders hanging in a ring that I can orient any way I want and get some more standard alignments for comparison. The poor babies hate being shuffled around, but they also like hanging stationary, so it might work — the initial manipulation might get them agitated, but then if I’m patient they’ll settle down and pose for me.

Isn’t it fun to tinker in the lab?

Where’s Alex Jones when you need someone to scream about scary science?

The word is “necrobotics” — using science to reanimate corpses. It’s still necromancy. This one lab is taking advantage of the mechanics of spider limb movements to use their dead bodies as robot hands.

Unlike mammals, which move their limbs by extending and contracting opposing muscles, spiders move their legs via hydraulic pressure. More specifically, they have a “prosoma chamber” located near their head which sends blood into the legs as it contracts – this causes the legs to extend. When the pressure is released, the legs close back in.

You can see where this is going. All we have to do is apply a little pressure and the limbs will extend, so you can just slide a needle into the chamber and presto, you can make the dead spider dance like a puppet. One thing that surprises me is how easy it is, using just a hand-held syringe to pump up the limbs.

It’s a rather gimmicky approach, and I don’t believe for a moment that it will ever have any practical applications. You’d have to murder a lot of spiders, and it sounds like they’re only going to have limited utility. It’s the same reason we can’t use zombies as Amazon warehouse workers — sure, they’d be cheap, wouldn’t unionize, and you could work them nonstop, but after a few days to a week their arms would rot and fall off.

Jeff Bezos has probably already done the analysis.