Web Wonderings

A spider begins spinning its web by crawling up to some choice vantage perch and reeling out a test line—a sticky silk thread that a breeze will carry to a distant stationary object, to which the silk adheres. Once the far end of the line sticks to something firm, the spider slides down the silk, thickening and strengthening it as she goes. This strong line then becomes an anchor thread that will later support the web, after the spider similarly constructs a couple of other anchor lines.

It's a rather haphazard process, as the spider cannot control where the opposite end of the anchor lines will attach. Thus, the orientation of the web is determined more by fickle breezes that waft through, rather than the intent of the spider.

Smart, successful spiders try to establish their webs in locations where many tasty insects will be flying—to be suddenly trapped in the silky snare. I would assume that evolution has taught a web spider to pick a high traffic zone—otherwise it starves. I doubt that evolution, however, has yet endowed spiders with ways to manipulate the wind, so there is a definite degree of chance to the process. Specifically, the orientation of the web is not within the spider's purview. 

 

So even a smart spider may end up fashioning its web in a direction that has little chance of capturing many bugs. For example, I am sitting in my outdoor tub tonight, looking above me, and seeing a spider's web that is nearly flat against the wall. I don't think that many insects will be intending to fly into the wall tonight, so this web strikes me as one that will see minimal bug traffic. Had the breeze blown that first anchor line in another direction, the spider may have been able to orient its web perpendicular to, or protruding out from the wall—much more likely to snare passing insects. Ahh... the vagaries of the wind.

Another intriguing aspect of spider webs I often ponder is the fact that birds can see into the ultra-violet (UV) range of the light spectrum, and since a spider's web reflects UV light, a bird can see the web and avoid flying into it. This capability is an advantage to both the bird and the spider: the bird doesn't get its feathers coated with sticky silk goo and the web is not destroyed. So if birds have UV vision, I wonder why some insects—locked into a perpetual evolutionary arms race with spiders—have not also developed UV vision. There's another area of research for someone.

(As an aside, a recent development in window construction is to glaze windows with a UV-reflective coating. Birds are far less likely to fly into these windows and kill themselves, because they see the glaze and it stops them, but humans cannot see the coating and thus view the window as transparent. And some of us walk into them.)

Yet another web wondering I have: As I walk through the woods in summer, along the many paths I have created, I keep wandering through spider webs and having them splay themselves across my face or along my bare arms. I'm constantly struggling to wipe off these sticky structures. It can cause a pleasant stroll through the woods to degenerate into a yucky dance, in which I'm striving to wipe off web particles that I can't even see. I hate to destroy a carefully-crafted web, but I can't see them—not having been blessed with UV vision like birds.

This makes me ponder the fact that many of my paths that wander through the woods are also used by deer, since they are smart enough to see that it's easier to follow my paths than forge their way through the tangled underbrush. Deer must also at times find themselves wrapped in spider web strands. How do they deal with it? Does it irritate them as much as it does me? Might they get distracted by the damn spider webs and lose crucial alertness to their predators?

I would be grateful if deer were as tall as I am, since they would then clear out many spider webs for me and make my walks nicer—but they are just not tall enough to sweep away the webs at my face level. They're too short. Hmm.. I wonder if I could breed deer with giraffes, to create a tall, long-necked deer, that would clear out spider webs for me. That sure sounds like another kind of ground-breaking research that would benefit mankind... at least this man.