Continuing the saga of our efforts to track down spiders…we’ve had some success.

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My wife and I are getting serious about this spider hunting business. We lit some torches and delved deep into our basement. I went as a dwarven fighter, she was an elven enchantress. It was terrifying.

You must understand that several years ago, when we still had teenagers at home, our basement was a hotspot for carousing. Many were the XBox battles waged in that space, the nights were full of shouts and gunfire and raucusness, and many Cheetos were consumed there. Then our offspring departed, and it fell silent and abandoned. We stripped out much of the furniture, removed carpeting, cleaned it all out, and it did fall into darkness and neglect. We braved the first level today.

The cobwebs are impressive and dense, and they were decorated with the shriveled corpses of many pholcids, and also the long-drained bodies of pill bugs, centipedes, and millipedes. We sought out any theridiidae, but they were absent. It was like a tomb.

Everything was covered thickly with webbing though, like the electrical system. Look closely, and you might see a pholcid embracing the grey box — it’s dead. I nudged it, it didn’t move (live pholcids will start gyrating in their webs if disturbed). One has to wonder what it is guarding.

I looked into the crawlspace. That was too awful to contemplate, too infested with webbing everywhere. No one has entered that cavern in decades, so we retreated. I think we’ll have to go up a few levels before we dare plunge into that nightmare.

We retreated further and turned the corner to escape when we saw…

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I went for my morning stroll this morning, checking out spider haunts. My garage is still destitute, with nothing but dead husks and cobwebs. I walked over to the science building, and checked a few places that I knew were crannies where cobwebs and insect parts and spider poop could usually be found — nothing! They were shiny clean! I guess our magnificent custodial staff had been scrubbing unusually thoroughly for commencement. I’ve still got my lab spiders looking sleek and plump, but they’re all female, and I’m desperate for male spider juice right now.

I consoled myself by making my final travel details to the American Arachnological Society meeting next month. I’ll get my spider fix one way or another.

Then I was reading a This American Life episode about spinelessness. It’s about the vertebrate bias in research publications and funding. Malcolm Rosenthal is deploring the fact that invertebrates are relatively neglected.

Our findings can be summarized in two major points:

First: The warm-blooded vertebrate skew was intense. Almost 85 percent of described species are arthropods, but more than 70 percent of publications were on vertebrates. Birds and mammals alone accounted for well over 50 percent of publications, despite representing less than 2 percent of all animal species.

Second: In a world where citations are used to measure impact, publishing on understudied systems comes at a cost to the researcher. Publications on vertebrates received more citations on average than arthropod papers. They were also far more likely to be “blockbuster” publications with more than 100 citations.

He’s right. You can’t deny that there is a strong bias at work. Back in the early days of zebrafish work, we often made the argument that these are honorary invertebrates when we were talking to other developmental biologists, because they do have a lot of the advantages of model systems in that group, but in our grant proposals we turned around and emphasized that these were true vertebrates, and that they had the virtues of relevance to research in human health and disease. We did our best to straddle that line.

And while Rosenthal’s evidence is true, I think he’s missing the real distinction. This bias is a consequence of a fundamental difference between basic and applied research. Basic research is all the stuff he and I love, where we just care about how the world in all of its richness works. Applied research has a focus on science that helps us, the human species, and because we’re such selfish assholes, that’s where the lion’s share of the moolah goes. Look at the names of the big funding agencies: the National Institutes of Health, the National Cancer Institute. That’s where you apply if you want to make a case for research that contributes to our understanding of human health and disease. You can apply for research grants to study, for instance, zebrafish, or even insects, but you’re going to have to link it with some relevance to Homo sapiens.

You want to study some other organism, because it is interesting in and of itself, and might tell you something fundamental about biology? You apply to the National Science Foundation.

The budget for NIH is $37 billion. The budget for NSF is $7.8 billion. Enough said. Even if you convince the agency to fund your research on some fascinating, little known organism, some jerk in the legislature is going to proxmire you and whine about wasting money on bugs. If you avoid the spotlight, you’re still going to that family reunion this summer where Uncle Dork is going to sneer at you and wonder what the hell you do for a living.

I agree that there should be more support for more diversity in topics in science, and I really want to see more support for basic science, but that’s going to require a huge shift in science priorities. I’m all for a National Spider Institute that is well-funded by congress, though.

I’ve spent all winter doing the book-learnin’. I’ve got so much unfocused spider lore stuffed into my head that I expect it to hatch and little spiderlings to start creeping out of my nostrils. I really need to start applying this information and working with real animals, so every day I prowl around looking for eight-legged beasties to study, and every day I shake my fist at the weather which hasn’t gotten around to any sustained warmth yet. It’s getting a little frustrating. I also have a group of students I’d like to deploy, but it’s all empty cobwebs right now.

They’re out there, I know it. I see an occasional salticid or pholcid indoors, I’m starting to see flies and other prey buzzing around, I’m expecting an explosion of spiders any day now.

To the relief of many, I haven’t been saying much about my lab spiders lately, and there’s a good reason for that — they aren’t doing much. They’re all females, they’re not producing egg sacs, and despite checking daily, I’m not finding any Parasteatoda tepidariorum in the wild, either. I think they’re in hiding, reeling away from our horrible winter weather, and we haven’t had enough spring warming yet for them to emerge and start spawning lots of little babies for me to use to replenish the colony.

I miscalculated. I started with a small group of about a dozen spiders and several egg cases before the winter hit, and I clearly need a larger colony to maintain a balance of the sexes, because the females occasionally chow down on their partners, so I was seeing the male population in constant decline. Then I also failed to sort out the sexes in the second generation, because I couldn’t tell them apart.

Adult male and female P. tepidariorum can be easily distinguished, because the males have these massively enlarged pedipalps hanging off the front of their face — I can easily tell them apart with the naked eye, they’re so distinctive. These palps are a sperm storage and intromittent organ, specific to each spider species, which they use in a lock-and-key arrangement in mating, so they both deliver sperm and guarantee that they’ll only mate with conspecifics.

I’m sure the spiders will be back soon, and I’m looking up all kinds of stuff on recognizing sexes in pre-adult spiders so that I don’t repeat this year’s mistakes again. Then, jackpot: this paper on Formation and development of the male copulatory organ in the spider Parasteatoda tepidariorum involves a metamorphosis-like process, and it’s got exactly the information I need, and also is pretty nifty in its own right.

This is a close-up of the organ I’m interested in. Impressive and rather terrifying, isn’t it? Males have two of them, too, which makes me a bit envious.

Like I said, these just leap to the eye when you examine an adult, since they’re much, much bigger than the female palps, which are slender and relatively delicate. I want to know how to spot them in younger sub-adults, though, and so here’s a developmental series illustrating the changes that go on. What’s interesting is that after an earlier molt, the terminal part of the palp swells up like a balloon, literally simply inflating with hemolymph (blood) to form a fluid-filled shell with a little primordium (in orange) of the adult palp resting within it.

What’s fascinating here is that, in the subadult, the hemolymph will coagulate to form a stable matrix which may play a role in shaping the species-specific expansion of the primordium. So it inflates, fills with material that shapes development and then is gradually lysed as the adult cuticle grows and fills the space.

As the title of the article suggests, this looks familiar — we see something similar in arthropod metamorphosis, where the structure of the larva is actively broken down, basically digested with enzymes, and adult primordia (the imaginal discs) grow to replace the animal.

It also has me wondering if one of the reasons spider intromittent organs can be so labile, varying from species to species, is that this developmental process of interactions between a coagulated matrix and the primordium is highly plastic. The authors say it’s consistent within this species, but I’d be curious to know how sensitive the adult morphology is to fluctuations in that matrix.

Now I’m really eager to get more spiderlings so I can watch their organs grow.