Monday, December 7, 2009

Things that lurk in the basement

Spiderlings hatch from eggs.

Each one has eight tiny legs.

A spider has more eyes than you. Most have eight, and you have two.

A spider has two body parts. Across its web it quickly darts.

From a spider's spinnerets, sticky spider silk jets.

Spiders feel the frantic tugs, Of their favorite food; it's bugs!

Janet Bruno

Ah, the shady recesses of a corner of my basement. And a very cool spider web. To the average Joe or Joette, this would be an undesirable cobweb to be swept away.

Not me. I like spiders. And, within reason will keep them around. Why not? Look at it like this: most of these house spiders are going to stay in their webs, and their webs are pretty obvious. So, you know where the spider is.

But not so with all the little critters they are capturing and purging from the house on your behalf. All manner of tiny invertebrates hole up in nooks and crannies during the day, and emerge at night to explore your home. But they'll explore no more, once they bumble into the spider's lair.

I bet you've got one of the above webs, or at least have had one. It is the handiwork of the House Funnel Weaver, Tegenaria domestica, a frequently encountered species. The webs are typically hammocked in a corner like the one above, and they can last a long time. The spider will add to it daily, until the sheet web becomes a thick, silky blanket. The red arrow points to its funnel - the den in which the spider hides and awaits victims.

Closer view of the funnel, which is built into the corner of the web. She is in there, just out of sight. Drop a small cricket onto the web, if you've got one, and you'll see her pretty quick, though. House Funnel Spiders use the surface tension of the web to feel prey. When something jostles the silk, out rushes the spider and quickly dispatches the prey and makes a meal of it. Chances are, whatever it captures is something that you don't want in your house, either.

Terrible choice, eh? You keep the spider - hard to knowingly do, especially for an arachnophobe - and reap the benefits of a cost-free predator ridding your abode of undesirable little beasts that scuttle in the night. The tradeoff? You've got to have a pet spider.

Photo courtesy Dr. Richard Bradley
Mrs. Tegenaria emerges from her funnel. Fortunately for us, they are only a 1/4 inch or so long. Should the fits and spurts of evolution ever produce spiders that are the size of Canada Lynx, whatever humanoids scrabble about the globe at that time shall be in serious peril.

Before you brush that next "cobweb" into oblivion, first pause to think about the engineering marvel that you are laying waste to. Spider webs may represent the pinnacle in small animal engineering. Ornate and incredible in design, webs are designed to effectively snare prey in many ways, depending on the species. Some spiders can produce over a half dozen types of silk - some strands thicker, some thinner, some very glutinous, other silks non-sticky, etc.

Some webs catch flying critters. Others specialize in grabbing ground and wall-crawlers, like our blog subject. Some species use specialized silken strands to knock bugs from the air and into a primary web. One species actually swings a silk rope like a lasso and snatches moths from the air!
Photo courtesy Dr. Richard Bradley
The last thing an earwig will see on this planet - the visage of a pouncing House Funnel Spider!

For some reason, certain animals spook us to an inordinate degree. Spiders most definitely do. But as is the case with most things, familiarity breeds appreciation. Spiders are interesting, and worthy of a closer look.

To learn more about Ohio's spiders, and even help contribute to our knowledge of them, visit the home of the Ohio Spider Survey.


Cathy said...

You've inspired me to head into my basement!

It's a bit tough learning to appreciate spiders, but well worth the desensitization.

The link to the Ohio Spider Survey will be enjoyable. I'm sending along my Bolus spider pix.

Dave Lewis said...

Thanks! I now the the perfect excuse for not cleaning our basement!