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.

Wonderful Web—Part 2

Once the web is completed, the builder will settle in to waiting—one leg lazily draped across a thread, so when an insect splats up against the web and tries to struggle free, the vibrations will alert the spider to charge out and secure dinner. The type of web that we humans are most familiar with are called spiral orb webs—simply gorgeous creations, made by (guess what?) orb spiders. Other kinds of spiders spin what are called tangled, funnel, tubular, and sheet webs. (See photos, previous posting.)

I contentedly gazed at this spider as it wove its miracle. I could see it zip in and out, building the radials after the anchors were strong, and then it moved in ever-widening circles, as it added the spirals. As long as this web stays in use, we call it a web. When (and if) it becomes abandoned and collects dust, we call it a cobweb. I wonder what names the spider uses.

I am very grateful for spiders building their webs around here and snacking on insects. The populations of other insectivores—bats and songbirds—are dwindling, so we value every spider’s contribution to check insect overpopulation. 

In mid-to-late summer I run into many spider webs during my walks through the woods. It’s rather irritating to be enjoying a hike and suddenly feel the threads of a web wrap around my face, stick in my beard, or slither along my arms. The sticky threads cling stubbornly to me and the strong anchor threads almost threaten to trap me. In self-defense, I have taken to carrying a small branch with many twigs splayed out at its end. As I walk along, I wave the branch ahead of me, to intercept the webs before my nose does—looking like a defrocked, bearded priest, blessing the forest as I wander. I almost wish I knew a few words of Latin to utter, to add to the image.

I regret destroying the efforts of a spider’s web work. I wish there was a way I could see the webs coming, so I could detour around them, but, unless it is caught in sunlight, the web is essentially invisible to me, as well as to insects. (Interestingly, birds, who can see in the ultraviolet portion of the light spectrum, can see the web and avoid flying through it—to both the bird’s and spider’s advantage. That’s to the bird’s benefit, because I don’t think they can pull out a handkerchief and wipe off the web threads, as I do.) Maybe I could invent an ultraviolet spider-web spotting device that I could don for my walks, to keep me from destroying those hard-earned webs.

Granddaddy Red—Part 2

One of these harvestmen visited me the other evening, as I soaked in the outdoor tub. He had an attractive red body (most of them are gray or brown, so that caught my attention right away). I’ll call this guy “he,” because he was rather small, and male harvestmen are more diminutive than “harvest women.” Males are also more colorful, and this guy was pretty snazzy looking. So I’ll call him Granddaddy Red, or just Red for short.

I have a wooden paddle laid across the top of the tub, with which I occasionally stir the water, to even its temperature. (On winter nights, the water near the bottom of the tub cools quite quickly and needs to be stirred often, lest my butt get cold.) I first spotted Red as he sauntered down the paddle, towards me. When he reached the end, less than a foot from me, he stopped, waved a couple of legs out into space, and seemed confused that his plank road had come to an abrupt end. He stood still, lifting first one leg then another—appearing to be testing the solidity of air. Since I don’t wear my reading glasses in the tub and dusk was rapidly approaching, I was left wondering what he was up to. Guess I’ll have to live with the mystery.

I soon lost track of Red, as I sunk back into my soaking reverie. Darkness began to descend. A few minutes later, I absent mindedly picked up the paddle, stirred the water, and set it back down again. Something tickled the back of my hand. It was Red! My hand had apparently given him a way to continue his stroll forward. Not wishing to drown him. I tried to urge him back on the paddle, but he was having none of that. “Been there, done that… I’m moving on!” So I held my hand out to the wall next to the tub and Red promptly stepped off, climbed up the wall, went over the top, and was gone into the night. He’d found a way to keep heading south, using my hand to boost him along. Farewell, Red! May the road rise to meet you.

There is an urban legend that, although daddy longlegs are very poisonous, their fangs are too small to puncture human skin. As is the case with most urban legends, neither of these beliefs is true. First, they have no venom. Second, their fanglike mouthparts are able to take a harmless bite out of you, but why do so when you may get squashed in the process by the two-legged monster? No, they are innocuous.

In fact, harvestmen are quite beneficial to our world. They are scavengers, chowing down on decaying plant and animal detritus. They are also helpers in the garden, since the other half of their diet consists of aphids, flies, mites, wee slugs, and other tiny pests. They are mostly active at night, so we don’t get to watch what they are up to.

American Indians called them “Grandfather Graybeard.” I find it fascinating that different cultures often have such similar names for nature’s critters. So why is a dragonfly called an “eye-poker” in Sweden and an “adder’s servant” in Wales?

Granddaddy Red--Part 1

One of the more intriguing insects that we have around here is really not an insect at all: the daddy longlegs or granddaddy longlegs spider. But then it’s not a spider either. So, is it a bug? No. Then, what the hell is it? The best and entomologically correct description is “harvestman.”

Let’s back up a little. An insect is defined as a little critter that has six legs, three segmented body parts, antennae, and wings. OK? A spider has eight legs, eight eyes, only two body parts, no antennae or wings, but has spinnerets (their silk-producing organ). OK? A harvestman is similar to a spider, but does not make a web (has no spinneret), has only one body part, and only two eyes. The harvestman is more closely related to a scorpion than a spider—though it has neither venom nor fangs. OK? So, what’s a bug? Well, it’s an insect (so it does has six legs) but is distinguished from an insect by having sucking, beaklike mouthparts. OK? Confused? So am I. It’s no wonder that we common folk have a struggle understanding entomologists.

Let me get back to the one particular critter I started with: the daddy longlegs… the harvestman. From any perspective, they are an odd-looking creature, with their small, round, one-part body, supported by incredibly long skinny legs. If its body size were as big as a human, each of those legs would be some 50 feet long!

Harvestmen are one of the most ancient animals on the planet—dating to some 400 million years ago. That predates the dinosaurs by a long shot! There are over 200 species of harvestman in North America alone. They come in many different sizes and colors, but all of them possess those ungainly long legs. And speaking of those legs, one of them can easily detach, if a predator attacks them and grabs a leg (which is likely to happen, given that they are mostly all leg). What’s more, the lost leg continues to twitch on its own for several minutes, which is Mother Nature’s way of confusing the attacker and giving the daddy longlegs a chance to run (seven-legged) away to safety… sans one leg for the rest of its life, but alive.

There are a few other peculiarities of harvestmen, but we’ll leave it at that for now. Well, OK… one more. Even though it has eyes (just two of them, remember?), they can’t see much at all, so its other sensory capabilities must make up for that loss. Mother Nature has compensated by allowing its second pair of legs to act sort of like the eyes, nose, and tongue on humans. Weird, eh? But remember, they have been around for nearly half a billion years, so they’ve gotta be doing something right.

More on Granddaddy Red next time…

Soggy Spider—Part 2

In a few minutes my arachnid friend slowly began to move its pedipalpi. (Pedi-what? At the time I had no idea they were called this. I later consulted a bug book, to learn what they are and what their function is. Fact: pedipalpi are small, leg-like appendages to either side of the mouth of an arachnid, and are usually a fraction of the size of its eight legs. On a scorpion, however, the pedipalpi are longer than its legs, and a stinger is located the end of each pedipalpus. OK? On with the narrative.)

On the end of my spider's pedipalpi I saw tiny hands or pincer-like objects, and the spider began to use them to groom the adjacent leg. Was it wringing off the excess water? It first bent and then elevated a leg, as it continued to stroke downward on it.

Ever so slowly, it worked on the other legs and then began to move its whole body, as if gradually recovering the ability to do so again. I admired its body—a beautiful shade of gray. It was bulbously shaped and handsome. I watched its round bulk quiver and very subtly change shape and fill out, ever so slightly. Was it breathing? Was its stomach convulsing with all the water it had swallowed?

I sent my friend healing energy. I apologized for having the bucket of water there and for the near-drowning it had experienced. I reached out and touched its body, ever so gently, to soothe it. It recoiled a bit. OK, it didn't receive my touch as a caress, so I kept my hands to myself. I wanted to pick it up and bring it closer to my eyes, so I could see better what was going on, but resisted. I wondered why I held back. Was I respecting its space and deciding not to bring it up close to my nose and frighten it with my gigantic puss? Was I responding to archetypal fears that people have of arachnids? The possibility of getting bit did make me pause—even though I had no idea of how likely it was to strike out at me.

I sat there watching the spider from across a wide gulf of ignorance. I tried to open myself to its world and intuit what was going on and what was important to it. I once again apologized for the bucket of water—useful to me but a potential death trap for it. Not sure there was much more I could do—except to leave it alone, hopefully to recover—I left, still feeling regretful and a bit deficient in my abilities to understand and help. Awhile later I returned to the hot tub area and the spider was gone—hopefully carrying on its life in a much drier environment. Maybe I could place a screen over the bucket?

Soggy Spider—Part 1

No matter how careful I am about not harming innocent creatures around the homestead, it inevitably happens that I do. I can’t completely avoid it. For example, when I walk across the yard, I may inadvertently step on a harmless ant or two.

The space we occupy on this planet is often earned at the expense of another creature—either by pushing it out of our niche or by outright killing it, either for food or just because it happens to be in our way. Nature usually achieves an exquisite balance between species that occupy the same territory—a balance that often sees them cooperating, but often also requires that they compete and that some of them expire in the process.

I have written before about how we do intentionally kill some so-called non-innocent and aggressive critters—those who have it as their intention to take over and rid us of “their” domain. House-invading ants and termites are examples. But there are countless species of plants and animals that are doing no harm to us, other than maybe being underfoot. One aspect of my developing a degree of sensitivity to the rights of these inhabitants to be part of my immediate surroundings is to try to understand them and discover ways in which we can cohabit peacefully. Over the years we’ve learned to do this with several insects and “weeds,” that we once considered obnoxious, but later came to see were quite harmless and even—once we purged ourselves of a little ignorance—could come to see them as beneficial partners.

Despite how hard I work not to harm our animal neighbors unnecessarily, however, I still do. Some of the harm is done simply because I don’t understand them well enough, and some is due simply to lack of sensitivity and attention. Here’s an example of the latter.

Planning to take an evening hot tub last year, I prepared to get it ready for a refill one day. Sitting beside the tub is a bucket of cold water that I keep for pouring over my head during a soak—to try keep my brain temperature low enough that I don’t fry any more gray matter than necessary, as I steep my body for a couple of hours in the hot spa. Picking up the water bucket to empty it out, I saw a spider sitting on the bottom.

Periodically I find critters who have crawled or fallen into the hot tub or the water bucket beside it—either floating on the top or having sunk to the bottom. Too many times I find them drowned. I always feel regret and apologize for having such a watery death trap awaiting them, and ponder what I might do next time to lessen the drowning toll.

On this occasion, however, the spider was neither floating nor dead. It surprisingly sat on the bottom of the water bucket, weakly flailing its legs about—not seeming to be in a panic, but very slowly moving its eight appendages.

I carefully emptied the bucket out, trying to deposit the spider gently on dry ground and not swamp it with a tsunami of water. Might it revive? It laid there upside down, a wet lump of a soggy critter, looking pretty sad, and no longer moving. I carefully turned it over and was surprised and delighted to see it open up a bit and stretch its legs out, looking almost normal. I happened to have a pair of reading glasses in my pocket, so I put them on and crouched down to inspect the soggy fellow. It sat there motionless.

Conclusion of Soggy Spider next time…