Spider Math


I have spent many hours today, counting spiders. I’m trying to keep track meticulously to figure out where the danger zone in spider raising is, and I don’t think I’ve reached it yet. I’m dealing with 3 clutches of spiders from 3 different mothers and 3 different fathers (they were caught in relatively different locations), and I’m simply tracking numbers right now.

Runestone line, 16 days old: 22 spiders, 96% survival, density of 1.1/vial.

Horticulture line, 15 days old: 94 spiders, 90% survival, density of 2.2/vial.

Myers line, 14 days old: 71 spiders, 93% survival, density of 3.0/vial.

There’s an accidental experiment in there. The first hatching from the R line was small and manageable, we were able to quickly and efficiently move them into vials, no sweat. They’re mostly living as single spiders in each vial.

The H line, on the other hand, just erupted with lots of spiderlings and we were a little overwhelmed and rushed. A fair number simply escaped, some we just gave up on and left in the cage with their mothers, and we were straining to get them all contained…so we had on average 2 per vial, and the max was 5 in a single vial.

The M line also taxed us, because I ran out of racks to store all these tubes. We tried to get as many as we could into the available slots, so there you go, on average 3 spiders per vial. I could at least look and see if the density in the first few weeks of mobility made a difference in survival.

And no, it doesn’t seem to. In fact, most of the deaths were in vials with single spiders, which makes me wonder if there might be some cooperative work in bringing down fruit flies, which are much bigger than the spiderlings. I did see, though, that big size disparities are emerging — some individuals were twice the size of their siblings in the same vial. I haven’t seen any sign of cannibalism yet, but that may arise if I don’t keep everyone well fed. Which reminds me, I’ve got 187 spiders down in the lab waiting for dinner.

Comments

  1. wsierichs says

    I can predict your future. One day very soon, you’ll enter your lab and a long line of spiderlings will await you, each one holding up a tiny bowl and begging, “Please, sir, may we have more gruel?”

  2. anat says

    And no, it doesn’t seem to. In fact, most of the deaths were in vials with single spiders, which makes me wonder if there might be some cooperative work in bringing down fruit flies, which are much bigger than the spiderlings.

    If true, that would be an example of the Allee Effect

  3. blf says

    Spidermath, Spidermath, does whatever a camel can
    Solves a field any size, proofs of theorems just flies
    Look out, here’s the pen of Spidermath
     …

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