I think it’s the idea of living in your home for 16 years and never leaving it except for brief forays to leap out, kill, and eat passers-by.
I still have questions, though. What about sewage? How do they clean up the spider poop that accumulates? Also, they show a spiderling … are males more prone to wandering from home? How do they avoid getting eaten when they tap on the turret door?
First, the bad news. I now have no adult males, because Xena ate her consort, as I feared she would. I am beginning to suspect that she’s one of those radical feminist lesbian spiders who is going to kill every male she encounters. I don’t know if they successfully mated before the murder, and she hasn’t yet produced an egg case.
Also, one of my second generation spiders, a young female, abruptly died. Before she curled up and expired, though, she did produce an egg case, so maybe her line will live on.
The good news is that right now I am keeping an eye on three egg cases. The next few weeks will tell if can keep any spiderlings alive any more.
The good news: I’m getting roughly one new egg sac every week, so I’ve had one produced on 27 December, another on 4 January, and another this week, on 7 January. I can make progress with that level of production.
Except the bad news: that egg sac from December should have hatched out by now. I opened it up: mostly dead. There were a total of 35 eggs in it; 6 had made it to the postembryo stage, and then died; 4 had made it past the first instar, and then croaked; 24 were arrested in an earlier embryonic stage, and were clearly not going to make it any further. There was ONE second instar survivor, waving its legs weakly in the midst of the charnel house of its siblings. That’s not very good. I’m not even certain the survivor is going to make it — I put it in a little chamber of its own with a fruit fly it can try to eat.
The other egg sacs…well, I’ll have to wait and see. I isolated the one from 4 January, and like the December clutch, put it in a petri dish on a cotton pad, which I spritz with water daily. Unfortunately, I’m finding that the pad doesn’t seem to help, acting more as a dessicant, I think. So I threw out the cotton on that second clutch. I’m leaving the 7 Jan sac with its mommy, in a large vial. We’ll compare outcomes under those two conditions.
Another hypothesis for this problem is that my original wild caught stock produced vigorous clutches of spiderlings, where the majority were healthy and fine…and cannibalistic, which contributed to a rapid culling. All of the egg sacs recently have been the product of inbreeding between progeny of the extraordinarily fecund Gwyneth. So I’ve placed my sole remaining male, a son of Gwyneth, in the company of a daughter of Xena, and will, I hope, get a new outbred clutch to compare. Or maybe Xena1 will consume the puny male. It was tough to get Xena0 to put up with any mates at all.
It would be interesting if Parasteatoda were sensitive to genetic inbreeding, rather than this low output being a result of my poor spider husbandry skills. I’m so used to zebrafish and flies that don’t care if you cross an individual with its sibling, its offspring, its parents, its grandparents (The Aristocrats!), but it is possible that wild species that engage in more mixing might be carrying a higher load of recessive lethals…although I’d also think there’d be limits to how much mixing there’d be in a synanthropic species with limited mobility in adults. Maybe there’s a lot of juvenile ballooning going on that I’ve missed? I’ll have to keep my eyes open in the spring, and see how my garage gets repopulated.
I’ve also noticed something strange going on in my brain. The questions I’ve been asking myself have been shifting from the generally embryological to something more ecological — I might turn into an eco-devo guy yet.
Just a little bit. I tore open a tiny corner of the one egg sac I have right now, and it looks like a batch of fine healthy eggs, and then I quickly folded the bit of sac over it and restored it to the incubator. I’ve been maintaining moderate humidity for it, and it seems to be working.
Otherwise, while I’ve been waiting for the spiders to reproduce, I’ve been cleaning up my lab fairly thoroughly. I threw out stuff from 15 years ago today, and the benchtops are looking tidy, and I washed a mass of dirty glassware. I’ll have to give everyone a video tour once I’m done. It’s been surprisingly pleasant doing mundane tasks around the lab space lately.
Somebody should have called Spider Protection Services, rather than dismissing this dangerous man.
Quick update, nothing exciting. The colony has been cleaned up and fed, I’ve got an egg case made on 27 December that I am not touching at all, other than to move it to chamber that I’m maintaining at a constant temperature and moderate humidity. With any luck, I’ll have spiderlings by the end of the week.
I’m still hanging on tenterhooks, though. I’m down to ONE (1) male, who gets rotated around to each of the vials (except to Vera’s — she’s a male-eater). I’m hoping a) he doesn’t get eaten, and b) I get a viable egg sac, otherwise I’m not going to have any embryos until the weather warms up and I can find new spiders around town. To get a sustainable colony, I’m thinking I have to get up to around 50ish adults, which is easily doable.
To look for spiders, of course. Mary and I were getting into the spirit of the season and were surveying the area for spiders this morning. We were heartened by the fact that she discovered a salticid in our house — I’d given up on looking, assuming that no self-respecting spider would be out and about in late December in Minnesota, but there it was. So we donned our headgear and started scrutinizing window frames and dusty corners, and we also trooped over to the science building on campus and checked out the hallways and the basement.
Mary caught me in dynamic action pose, staring at cobwebs.
Unfortunately, the spider population was sparse or in deep hiding. We found another salticid in my office, and the husks of a few dead pholcids (lots of pholcids thriving in our basement, though), but no Theridiidae. There were also a few abandoned funnel webs outside. One problem is that the university custodial staff do a really thorough job of demolishing cobwebs and making an inhospitable environment for spiders…and I don’t think there are very many insects to eat there, except maybe in relatively unreachable places, like crawlspaces.
It’s also cold outside. I’ll be interested to see how the population changes in the Spring.
I was bragging about Vera’s great skill in capturing multiple prey in minutes, so I thought I’d show you. Basically, whenever I put live flies in the spider’s vial (I feed her 3 times a week), she is off like a shot, immediately charging in to snare them.
She reminds me a lot of my cat that way.
It was tricky keeping her in frame and in focus, but I think you’ll get an idea of how spiders use their webbing to immobilize prey.
Also, I’m going to start doing everything “spider-style”.
Quick update: here’s a shiny new Parasteatoda postembryo. Nothing exciting happens in this video — it’s nothing but 3 minutes staring into the eyes of a baby spider. It twitches a bit. It waves a leg around, floppily. But so much is happening in its nervous system!
This is one member of the new clutch of Gwyneth’s grandchildren. I’ll be sorting them out this weekend and putting them in individual vials, and maybe by early March they’ll be making Gwyneth’s great-grandchildren.
I just got back from tending my herd, who are all doing well. I’m anxious to get more egg cases, though, so I’ve been feeding them more and frequently — I gave each vial of spiders a half dozen flies today. I noticed some behavioral differences. The young adults each quickly moved on a fly, immobilized it, and settled down to biting and eating. Vera, currently the most senior spider in the colony, had a different strategy: she would scurry over to a fly, quickly wrap it up, and then move on to another. She had 5 flies immobilized and writhing in lightly webbed cocoons in about 30 seconds. It reminded me of calf-roping at the rodeo. I was impressed. Then she rubbed her forelegs together and cackled something vulgar in spider language* before moving back to her first captive and turning its guts into soup.
The embryos in the one egg sac I have are coming along nicely, showing nicely differentiated legs. I’m avoiding manipulating them much, since I’m more concerned about getting a strong, healthy third generation going, but they look to be about stage 13-14 by the standard staging series, which means I’ll probably have post-embryonic spiderlings by this weekend, and am going to have to spend a bit of time sorting them out into separate vials. This cohort of spiders are all inbred grandchildren of Gwyneth. I’m sad to say that Vera has not managed to produce any viable offspring for the colony — I did hear her sneeringly announce that she was not a breeder, and in particular wasn’t going to breed to produce servile offspring for an inferior species.
I’ll put the diagram of the developmental stages below the fold, so arachnophobes may not want to go any further, even though these are cute li’l babies in the image.
