Tuesday, June 03, 2008

Porch Spiders: End of an Era

It's been a while, but so much is happening now that spring is well underway (or nearly over) I thought I better start doing some updating.

The ceiling of the front porch has been deteriorating rather badly over the last few years, so a couple of days ago I pulled it down to get ready for the new one my brother will be putting up in a few weeks. There was no way to do this without displacing the porch spiders, who reappeared from wherever they spend the winter not long ago. I knew this day was coming, so I'd intended to move the eggs from last fall before they hatched, but I was too late, so there were also masses of young of the year to move as well.


There was a rather gruesome drama going on the day I did this, so before I got started I snapped a couple of pics.

I've not yet been able to identify these spiders to my satisfaction, but after a few years of close observation, here's what I suspect is their life history. Eggs are laid in the fall to hatch the next spring. Moms are in their second year, and disappear after they lay their eggs, so I think they only live for two years. Newly hatched young, those that survive, spend their first season growing, overwinter, and then in their second season reproduce. They grow quickly through the summer, mate, and lay their eggs. Last year, one spider was too late laying her eggs. The weather changed just as she was spinning the case for them, and she never finished.

Last year I got to see a lot of courting (at right, courting couple from last July), fighting among males, and mating (not terribly unlike fighting--a little scary). Over the years I have also spent lots of time observing their feeding. These are web spiders, active mainly at night, they wait for prey to hit their webs, then swoop in and wrap them up, sometimes feeding immediately, sometimes saving them for later. They are relatively large spiders, but will take on prey much larger than themselves when the opportunity arises. One got a very large dragonfly last year, for example.

But, I learned, they do not always sit and wait.

Scoping out the scene.

As soon as the newly hatched spiders started to spread out, two adults swooped in to hunt them. This is so out of character for these spiders, I suspect that this is a special tradition for them--cull the young, get a big meal, let this generation invest in the next.

Baby spider, there's nothing better!

So I was very glad to see it. I would have missed it if the timing had been a little different, and I was also able to move quite a few of the young ones, and most of the adults to trees and shrubs, after watching for a while, in the hope that they will like these almost as much as they like a porch.

Did I say "end of an era"? Well, maybe not. I didn't manage to move them all (a couple were well hidden), so maybe after everything settles down, I will once again be sharing the front porch with a couple of these beautiful spiders.