Cellar Spiders Carrying Eggs

2013 July 17

The door covering the outside entrance to the basement of our old house[1] is a great place to find Cellar Spiders. While I’ve photographed this species before, there is a particular behavior of theirs that I wanted to document. And so, on August 11, 2012, I opened up the cellar door specifically to find females that were carrying their eggs in their jaws. I found two. There was this one:

and a few feet away, there was this one:

Their eggs were not identical. The first one had eggs that were about half covered with thin white lines,

while the second one had eggs that were unmarked.

What I suspect is that the eggs with the white lines were about ready to hatch, and what we are looking at are the baby spiders’ long legs all pressed against the egg surface. And the other set of eggs were more freshly-laid, and so hadn’t developed any visible structure yet. The emerging babies would have legs that were longer than the diameters of their eggs, so it probably would have been rather like watching flowers bloom to see them hatch.

A mother spider obviously can’t eat while carrying the eggs like that, but they evidently hatch in a couple of weeks, which isn’t long enough for her to starve to death. And in fact, the female cellar spider lives for several years, hatching out a clutch of eggs every year.

Cellar spiders are well-adapted to the house environment, and in a warm house they are likely to produce eggs at just about any time of year. Under the unheated cellar door, though, they appear to produce their eggs mostly during the summer.

[1] When we bought our property, the house that came on it was a drafty old farmhouse that had a lot of deficiencies. After living in it for about a decade, we considered remodeling it, but it turned out that correcting the deficiencies would cost more than we had paid for the house in the first place[2]. So, instead, we built a new house next to it, and the old house is now a workshop/storage area[3]. And its basement is still a dandy place to find spiders.

[2] We didn’t actually pay all that much for the house (we bought the place more for the sake of the property than for the house), so it wasn’t hard for the cost of remodeling to exceed its value. Besides, as my father put it, “If you remodel an old house, you just end up with a remodeled old house that won’t bring much if you ever sell it. But for the same money, you could have a brand new house that is worth a lot more.”

[3] That’s the nice thing about owning about 9 acres of land – there’s plenty of room for building a second house on it, while still having a lot left over for other purposes. And now the old house is a good place to do things that would make a huge mess if we tried doing them in the house we are actually living in. Like extracting honey, for example.

2 Responses
  1. July 20, 2013

    Awesome! I want one.

  2. July 31, 2013

    3 acres with a house/workshop? I’m jealous! Great photos as always.

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