Too many spiders?

I admit, I might have a small problem. I came in to work this morning and found another egg sac had spewed out a bunch of adorable baby spiderlings. (This is a very low resolution shot, I hope the arachnophobes here can bear it.)

This is nothing new or surprising. I’ve had four egg sacs bear fruit since last week, so I’m getting used to it. I sit down and sort out all the spiderlings into separate vials, and tuck them away near the incubators. Not in the incubators — they’re all full of spiders already. They seem to do fine at room temperature.

Well, I think the future of the colony is more than assured at this point. If I raise 150 spiderlings to adulthood, I’d have to take over the neighboring lab spaces and maybe occupy the science building atrium, and I have about 15 more egg sacs waiting in various containers already. I’m going to have to draw a terrible, wicked line.

Future babies will not be coddled and given living quarters and free food. Instead, we have some experiments in microscopy and staining in mind, and they will be killed, quickly and humanely, thrown into fixative, and their bodies treated with various exotic chemical compounds before being mounted on a confocal microscope.

Oh jeez, I sound like a Republican.

FREEEEEDOOOOMMM! For a few days, anyway

Today is my last day of classes before Spring break, and it’s going to be a busy one. After I finish up lab today, I’m free! Except for grading an exam and lab reports, and having to tend the students’ flies until they get back, and feeding my own monstrous swarm of arachnids every day. Other than that, I get to sit back and take it easy.

So let’s do a live stream tomorrow! I’ve got some rage bottled up in me about idiots denying evolution and climate change, plus maybe I’ll reveal some spider breeding tricks. Live! On air!

I do have to get through the rest of this day, though.

Cobwebs as art

Spider webs, especially cobwebs, are so complex that it can get annoying. They’re also hard to photograph — so many thin threads going every which-way in 3 dimensions, it’s easy to get lost. I’ve been gratified lately to find that I can confine spiders to make mostly two-dimensional sheets using a wooden frame in a plastic container (they prefer natural substrates), but I have no illusion that this reflects the sophistication of their natural behavior. It’s mainly a good way to get them to pose nicely for me, and to simplify moving them from one place to another.

But some people manage to capture those 3-D webs.

“Forget about spider man and his meek two-dimensional webs! Even though spider webs have been around for at least 140 million years, we have never managed to preserve, measure and display their webs in a three dimensional form. Tomás Saraceno has opened our eyes to the intricate geometry of spider webs with his newly invented scanning instrument that digitized for the first time a three-dimensional web. In fact, there is no single museum in the world with a collection of this kind. His spider web sculptures are a breakthrough in both science and art, and thanks to his methods and technique he has enabled much needed comparative studies in mathematics, engineering and arachnology, opening new fields of studies.”

(Peter Jäger, Head of Arachnology, Senckenberg Research Institute, Frankfurt am Main, and co-author of the World Spider Catalog, 2015)

There are lots of pretty pictures at that link. Everybody loves orb webs, but cobwebs are much more intricate and confusing.

Spider sex is more complex than the binary paradigm

It looks like it’s time for me to go on a blocking rampage on Twitter, because the TERFs/GCs are flooding my account with stupidity. There’s only so much of that that I can take. The problem is that Graham Linehan noticed me, and the flock of dim & bigoted fanatics who follow him are piling on. One of them noticed that I breed spiders and thinks that is an excellent gotcha.

One thing I find gratifying is that sex-denialists like @pzmyers wibble on about sex being socially constructed and bimodal. But when they actually want something done (in this case breed spiders) – they suddenly know there are exactly 2 sexes and it’s the females that make eggs!

I make movies of spiders mating, as he notices, but somehow he thinks I’m a “sex-denialist” and that somehow this contradicts my position on trans rights. Surprise! I actually know how sex works. I understand that making an embryo requires a fusion of two gametes. I would think all of the trans folk he despises would be more conscious of these distinction than he is.

I also know the logical difference between the fact that many females make eggs, and the idea that all females must make eggs. I also know that even in spiders there’s more to sex than tab A goes into slot B.

I also have information on that. I’m mainly interested in spider sex as a means to an end — I need lots of embryos — but to get there I’ve been making observations of spider behavior. Every morning I move a male spider into a container with a female spider, slide it under a dissecting scope, and watch what happens. Sometimes courtship and mating are swift and dramatic, and I click a button and record the whole process, and that’s what you see. Sometimes they take their time, and I have to watch them dawdle and fumble around for a half hour before anything happens. Sometimes I give up and put the pair in an incubator overnight and hope something happens. Rarely, the female just murders and cannibalizes the male. Of the clutch of spiders that emerged in January, I’ve got 11 females who successfully mated and produced an egg sac; I’ve got 16 that spurned the male I provided and are effectively childless. Those I don’t record, because two wallflower spiders avoiding each other isn’t particularly interesting.

What’s going on? I don’t know. My focus isn’t on the behavior, but on the development of embryos. But who knows — maybe there are gay and lesbian spiders. Maybe some are asexual. Maybe there are timid spiders and bold spiders. Maybe some spiders are unattractive and no one wants to have sex with them. Maybe the Adult Spider Female is focused on her bug-munching career, and doesn’t want to make babies. Maybe some pairs of spiders have cellular incompatibilities that prevent fertilization. Maybe for some spiders the behavior works, but the plumbing is atypical. These are all interesting possibilities, and if a student were to come along and ask to make a quantitative analysis of mating behavior and reproductive success, I think there are a lot of good questions to ask and some useful studies to make, because sex, even in a small arthropod as driven by instinct as a spider, isn’t binary, isn’t a question of did they or didn’t they, and exhibits a range of complex variation that I haven’t tried to plumb.

Other people are looking into that! A paper by Angelekakis, Turutzek, and Tuni (2022) looked into mating rates in Parasteatoda, and as I’d expect, it’s complex. Spiders can be choosy — the majority of females didn’t mate at all (as I’m seeing in Steatoda), and many would mate only once and then be done with the whole messy business (they store sperm, so one successful mating is sufficient for a lifetime of egg production.)

As usual, the TERFs/GCs try to ignore all that and shoehorn everything into a simple binary. It doesn’t work for spiders, and it especially doesn’t work for humans, who have layered on so many variations and subtleties and tangled them all up with non-reproductive cultural behaviors. This @nathankw nitwit tried to argue that sex can’t be bimodal because I can’t provide a single numerical parameter that shows a range of values for sex. The problem isn’t that I can’t, it’s that I can provide so many. Receptivity, courtship initiation, web twanging frequency, successful insemination frequency, dancing intensity, abdomen size, interval since last courtship, metabolism levels…I can think of so many measures that don’t exhibit the kind of fixed values that he wants for males and females. It’s overlapping ranges all over the place! In spiders! But he wants to pretend that human sex is simple, nothing but sperm and ova.

Graham Linehan really didn’t have anything to contribute, other than to claim my biology is a religion, and to add this silly little bon mot:

A biologist who pretends to believe that humans can change sex. What a time to be alive.

But if humans can’t change sex, why is this crowd so opposed to gender affirming care, hormonal treatments, and surgery? If sex is an unstoppable freight train that can’t be diverted, then let them continue with their ineffectual efforts to change sex. Except that they keep seeing the inescapable evidence that sex can and does change.

Angelakakis A, Turetzek N, Tuni C (2022) Female mating rates and their fitness consequences in the common house spider Parasteatoda tepidariorum. Ecology and Evolution, doi.org/10.1002/ece3.9678.

There be spiders under there!

Beneath that huge pile of drifted and shoveled snow beside my garage lies buried my compost bin, legendary home to many generations of spiders (especially Steatoda borealis) and maggots. I couldn’t seen any spiders before the last big storm, but now I can’t even get to it. It’s completely covered in an avalanche of snow.

This is probably just fine for the occupants. Lots of spiders overwinter by snuggling down under the layers of snow, and others just tuck away an egg sac and let the embryos rest quietly until the spring. I’ll be checking in as soon as it melts and it warms up a bit more.

Do spiders celebrate Darwin’s birthday?

It was yesterday, in case you forgot. Over the weekend, the spiders produced two more egg sacs, and they also ate one of my precious males.

To celebrate the fecundity, they all got big fat slow waxworms for breakfast today. They’re all off munching right now.

I tried to tell them that they ought to get romancing for Valentine’s Day, too.

I’d show you a picture of a big fat slow waxworm getting eaten by a very happy spider, but I’ve been avoiding horrifying you all with those closeup images of my beautiful charges. You can find the carnage on my Patreon or Instagram.