Happiness is a pocket full of maggots and spider eggs

Our compost bin is thriving! We found some new egg sacs inside it, like this one:

It’s strange. It’s orange. We suspect it might be Mimetus, the pirate spider, but time will tell. I took it into the lab and will have to wait for it to hatch out.
The other compost development is that it is full of squirmy busy maggots. I’m talking dense sheets of a multitude of swarming maggots. I scooped up some and brought them in to see if the spiders would eat them. They liked it! (The spiders, not the larvae.) This will be an alternate food source, at least over the summer. I think it’ll slow down a lot once the temperature drops below freezing.
In other news, I’ve been doing weekly measurements of the growth of my Steatoda triangulosa babies. They’re all (except one, sort of) growing well. Here’s a table of the mean dimensions of the young spiders.

I know, not exactly exciting, and I have to plod through more weeks of measurements. Note the big surge in length this week! That’s because they all molted on Day 22, and shedding that exoskeleton gave them more room to stretch.
I mentioned one spider was an exception. Spider #5 is looking a bit odd. Still growing, but suddenly their limbs and palps have gone pale…I’m hoping they’re not sick.

An important lesson

Do not make your observatory look like a giant pill bug.

That’s how you get giant spiders, you know.

Noooo! Too slow!

I’ve been tracking the growth of individuals in my Steatoda triangulosa colony, and finally have a whole 3 time points so I can estimate the spider growth rate. Behold, the first preliminary chart!

The line is a linear fit, which is not likely to be what I see in the end, but it’s optimistic, and I can’t really make many assumptions with so little data. But OK, if aiming to raise these spiders to a length of 1 meter, that’ll only take, with that assumption, about…a century? Yikes.

That rate is perfectly appropriate if they max out at 10mm long, like their mommy, but it’s going to be hard to take over the world with tiny little spiders like that. I guess I’ll have to go for numbers.

First I’ve ever heard of a food company wanting to use a spider for PR

There is a spider, Araneus mitificus, AKA the Kidney Garden spider, that sort of vaguely resembles the mascot (?) of Pringles potato chips. Surprisingly, the Kellog company, which markets Pringles, has embraced this idea and want to make the name “Pringles Spider” official.

There’s a petition and a website. If the name change is approved, which they think they can do by persuading “the decision maker” with enough signatures, the first 1500 signatories get one free can of potato chips. Who is the “decision maker”? They don’t know.

Pringles has added a petition to Change.org with the hopes that the International Society of Arachnology, the American Arachnological Society, and other organizations will “do what’s right and recognize this very real spider as the Pringles Spider.”

How awkward. The American Arachnological Society does not determine nomenclature, neither does International Society of Arachnology. You can send all the requests you want to them, and they’re just going to give you the side-eye and block you as spam. There is an International Commission on Zoological Nomenclature, but they have very strict rules about the assignment of binomial nomenclature, you aren’t going to change that. Common names are vague and often lazily defined by usage; you can call it the “Pringles spider” if you want, but it has no official weight.

There is absolutely nothing preventing Pringles from putting a photo of Araneus mitificus on all of their packaging and happily calling it the Pringles Spider. They could also make commercials with a smiling anthropomorphized spider touting their product, and get rid of the mustachioed cartoon man altogether. They don’t need a petition for any of that!

Go ahead, Pringles. I dare you. I double-dog dare you.

Spider engineering

Hey! I was watching my spiders do this just yesterday!

(a) An adult Steatoda paykuliana female of the family of Theridiidae (courtesy of Alessandro Kulczycki, Aracnofilia – The Italian Association of Arachnology). (b) A Steatoda triangulosa that captured a lizard (Podarcis muralis) by using lifting technique (courtesy of Emanuele Olivetti). Schematic of the technique used to lift the prey. (c) The prey is detected by the capturing threads and, once it is, (d) the spider starts to attach pre-tensioned threads to it. (e) When the weight of the prey is won by vertical component of the sum of the tensions the prey detaches from the surface and (f) starts to be lifted.

It was a feeding day. Little critters like Drosophila are easily handled — I saw one swoop down on a drag line to a fly walking on the floor, hog-tie it with a couple of quick flicks of silk, and then haul it up in one smooth motion. That was impressive.

However, these guys do kill and consume prey many times their size. I saw one snag a mealworm, which then went into a frantic writhing struggle and broke free, ending up on the floor of the container. The spider dived on it, trussed it up again, and then hoisted it up about 10cm to the heart of its cobweb. They are amazingly strong, and as the diagram illustrates, very clever about leveraging the structure of their web to secure their prey.

I have not tried feeding them small vertebrates yet, but the lab next door to mine is a herpetology lab, full of spider food. Don’t tell Heather Waye, she isn’t personally keen on spiders already, and hearing that they might have designs on her research animal would not be very endearing.

OK, I’ll stick to invertebrates.

Don’t panic, it’s just a spider bite

Fortunately, I’m not as interested in social behavior of spiders as I am in just general development, physiology, and behavior of individual spiders. Here are some recent cool things I’ve read.

I’m working with Parasteatoda and Steatoda in the lab, so of course I’m curious about their venom. Maybe you wonder about what those common house spiders are packing, too. Here’s a breakdown.

Relative abundance and expression level of genes encoding predicted venom enzymes and toxins. (A) Treemap chart of the main classes of venom-related enzymes and toxins present in Steatoda nobilis venom gland transcriptome. The size of the rectangles is proportional to the number of genes in each category, indicated under the labels. The colour represents the log2 transcripts per millions (TPM) of the median expression of the genes in each category. (B) Expression levels of each gene in each enzyme/toxin category. Dots represent the mean expression of individual genes across three biological replicates ± SD; purple: enzymes, orange: toxins.

What’s it all mean? A is showing us the number of genes involved, while B is indicating the expression levels of those genes. It looks like about a third of the genes are toxins, but that those are relatively highly expressed in the venom. The purples are not toxins, those are ordinary digestive enzymes. An important component of the venom is a collection of enzymes that break down proteins and fats and carbs, everything you need to turn guts into a nice soup. The oranges are the actual toxins — all the “latro” prefixes tell you these were identified in Latrodectus, the black widow. There is a lot of similarity in the venoms of black widows and false widows! That α-latrotoxin is the one that we vertebrates have to worry about. Do we need to worry about our common house spiders? Maybe a little bit.

We reveal the striking similarity between the toxins found in Steatoda nobilis venom and that of black widow spiders (Table 1). The most powerful toxin classes (α-LTX, α-LCT, α,δ-LIT) and the enzymatic machinery allowing the venom to more easily spread into the prey (metalo and serine proteases, chitinases) are both present in large quantities. This however does not mean that Steatoda is as dangerous to human beings as some members of the genus Latrodectus. If isoforms of potent toxins are present, our study does not provide information about their potency. Evaluation of toxin toxicity would need to be performed before any conclusion could be reached. Nevertheless, given the composition of the venom depicted in this study, S. nobilis should be considered a species of medical importance and there is no doubt that S nobilis (with Latrodectus tredecimguttatus) is one of the most dangerous spiders in Western Europe.

The easy solution is to not get bit. That’s not hard to do at all, these spiders are really not interested in you. Leave ’em alone, they won’t bother you.

If you are bitten — I’ve heard it’s a bit like a bee sting, although personally I’ve never experienced it — if you experience a strong reaction, the similarity to Latrodectus means black widow antivenin will be effective. As the paper says, though, they have nat assayed the potency of Steatoda venoms, and what I’ve heard is that they’re not as fearsome as black widow venom, so don’t panic. Besides, only one or two people a year die from the bite of the most deadly American/European spider, the black widow, while Steatoda has milder effects.

If you’re still worried, here’s a summary of recommended first aid. Wash the bite (infection is probably a greater danger than the toxins), use an antibiotic cream, and ice the area. Take ibuprofen and/or an antihistamine.

This invasive species hasn’t invaded my neighborhood

This is rather interesting: an article from the National Museum of Ireland describing the appearance of the noble false widow (Steatoda nobilis) in that country, in the late 1990s. I haven’t seen any of that specific species in my neighborhood, but apparently they are a significantly invasive species. We have lots of Steatoda and Parasteatoda here, though!

Most of us in Ireland have heard about this recent arrival, but few would know its scientific name, Steatoda nobilis. This spider is more commonly known as the noble false widow.

Interestingly, in an article published at the time (Nolan 1999), Myles Nolan tells the reader that a couple of weeks prior to the aforementioned Bray discovery, another person had found a great number of these spiders on their own property, approximately 250m away from the Bray residence. The author observed at the time that these spiders have a high reproductive rate, and that the spiderlings are inclined to disperse widely from the egg sac, perhaps accounting for this species’ ability to colonise easily.

The Museum specimen detailed in our acquisition register is, however, the first valid Irish record as an identified specimen was lodged with the Museum. That specimen (called a ‘voucher specimen’) is now stored safely in the Museum and is available for study and research.

As Ireland currently houses relatively few animals who pose a risk to human health, this new arachnid is now of great curiosity to the public. The reports, however, are over emphasised, and there is little for humans to fear from the noble false widow.

A recent report from the Irish scientific community however, showed that a common lizard had been preyed upon by this diminutive spider (Dunbar et al. 2018). The young lizard was discovered wrapped in spider webbing, with the noble false widow crouched over its head, presumed to have been feeding on it – a potential worry for Ireland’s only native terrestrial reptile.
The noble false widow can now be found in at least 17 Irish counties, all year round, both indoors and out (although more so the latter). They have a strong tendency to live on manmade structures and materials, such as steel, concrete and timber. Sheds, outhouses and boundary railings provide the perfect habitat for our new arrival.

Part of the reason for the relatively sudden appearance of Steatoda nobilis in the scientific eye, though, is the British tabloids, which had an absolute freakout over big spiders, playing up the nearly non-existent dangers and clutching their pearls over the observation of a few spiders near one of the Queen’s estates. It was ridiculous.

Increase in Spider Recording Scheme records for Steatoda nobilis in Britain parallels intensified
press coverage in the local newspapers (dark blue bars = spider records, light blue line = number of press
articles). The sudden massive increase in records seen in the last decade coincides with the first appearance
of the species in various other countries far from the native range in the Macaronesian islands.

I can vouch for Steatoda‘s eagerness to disperse — when I found the newly emerged clutch of spiderlings yesterday evening, they had nicely spread out equidistant from each other in their container, and when I opened it up, the race was on, with all the spiderlings on the edge of the mass rushing to get out into the larger lab. I think they don’t much care for their brothers and sisters.

The “high reproductive rate”, though, is a relative thing. My impression of Steatoda triangulosa and Steatoda borealis, the local species in the genus, is that they were sluggards compared to Parasteatoda. They take a month to develop from egg to spiderling, compared to Parasteatoda‘s week and a half, and they have much smaller clutch sizes than Parasteatoda. I’ve been sitting here feeling like the Steatodas take forever to get to the point I can work with them.

On the other hand, at the end of that month I am finding myself drowning in baby spiders…

Logistics are so important

I can’t really compete with Marcus and Charly in the big time construction and crafting projects, but I did make something that worked really well today. I made a fly-shaker. You know, like a salt shaker, only you shake flies out of it.

I’ve got a lot of spiders right now, all housed in individual vials, and I’ve got many more on the way. In particular, I’ve got 40+ baby spiderlings, with maybe a 100 more waiting to emerge any day now. I really want to keep them well fed so they’ll grow rapidly (and to Great Size, I hope), which means I’m feeding them every other day. This has been a clumsy process in which I put a few hundred wingless flies in a wide mouth cup, then cover it with a lid, and go down a line of spider vials using a paint brush to flick a few individuals into the loving arms of my babies. This is messy and awkward, because as soon as I open the lid to flick out a couple of flies, they all swarm to escape.

It takes 45 minutes to an hour to feed everyone, and it’s sloppy and a fair number of flies escape…to die, because there’s nothing for them to eat in the lab, and there are also escaped spiders that are thriving on their futile attempts to get away.

My fly shaker is simple: a plastic water bottle with a very small, fly-sized hole drilled in the top. I tape over the hole, use a funnel to dump a lot of flies into the bottle, and then open up all the spider containers. The spiders are well-behaved and will quietly rest in their web. Then I remove the tape from the fly shaker, invert it, and tap it once on each vial. Tap-tap-tap-tap-tap-etc. I did the whole bunch in less than 5 minutes! Then I was free to sit back and watch the gladiatorial spectacle as my spiderlings went into a frenzy.

I’ve been inefficient and working too hard. Now I can grow this spider army far more easily.

Maybe I should write a parenting book

I’m learning things from raising Steatoda triangulosa. Feeding time is a marvel: I recorded a very short video of the little spiderlings’ reaction to having a fruit fly thrown at them. It’s like instant implacable carnivory! They’re eager to leap onto their prey, exhibiting the same behaviors as the adults.

So, this is my idea of a good parenting book. Take your little human baby, and toss a small calf or a large puppy into the crib with him or her. Leave them to their business for a few days. Come back later and remove the bones and scraps, and toss them another one. Repeat until they’re old enough to hunt on their own.

I guess since they’re weak humans, you could give the baby a Bowie knife or something to compensate.

Unfortunately, my own children are all growed up, and it’s too late to try on them. My kids probably won’t let me try this with the grandkids. That means…