"Eeek! A spider!" Maybe it's the eight creeping legs or the sticky strands of cobweb that scare us. Whatever it is, few of us are particularly fond of spiders. Yet spiders are among the world's most fascinating creatures. Over 50,000 different kinds are estimated to live on the earth. Some huge ones, like the Mexican tarantula, are big enough to eat a mouse. Others are so tiny they are hard to see with the naked eye. All spiders can spin silk. But, unlike the larvae of insects which spin from their mouths, spiders have a set of tiny spinnerets in the back underside of their bodies. These spinnerets can produce different kinds of silk for a variety of uses. Some spiders can spin a line of silk one-millionth of an inch in diameter! Yet this single thread has such elasticity that it can stretch one-fifth of its length before breaking. Its tensile strength is surpassed only by fused quartz fibers. Steel is weak by comparison. Yet surely the most amazing achievement of the spider is that marvelous architectural masterpiece known as the web.
The spider's web is a construction job par excellence, as well as a strong and dangerous trap for catching prey. The striking beauty and symmetry of the web of the black and yellow golden garden spider (argiope) can be seen in the photo above. In building a web, the spider has to first fashion a miniscule, fan-shaped kite on the end of her silk-thread line and then sail it in the direction of a nearby branch or, solid object. Once this line is secured, she will bite through it, then inch along suspended between the two loose ends, all the while winding up the thread ahead and spinning a new strand in the rear. When these basic foundation lines are anchored, the spider begins the process of carefully constructing the inner portions of the web. She constructs a temporary spiral to keep the web intact, then goes about the business of spinning the sticky strands that will do the actual insect-catching. After that, the spider will polish off her construction work by cutting away the temporary threads. Unlike the insects that are snared in this tangle of lines, the spider has a specially adapted foot that enables her to freely move about the web. She also constructs her web at an angle that is slightly inclined from the vertical. This helps her to hang
A WITNESS TO THE GREAT CREATOR, orb-weaving spider (far right) pauses a moment before continuing its web wizardry. Spiders are preprogrammed to spin effective insect traps (below and lower right). Single strands of silk (center) show beads of sticky glue which help catch and hold spider's prey. — See PDF for Pictures.
to one side and further avoid entrapment. A special "telegraph wire" enables her to feel the presence of a blundering insect. And she can detect nonmoving victims by systematically plucking each of the threads that serves as a radial spoke for the web.
Do spiders "learn" to spin their webs, perhaps by trial and error? In an experiment reported in Scientific American, common cross spiders were hatched in small boxes and kept there until they were partly grown, then were transferred to large cages. They were immediately able to spin perfect webs! In other words, they did not begin their careers by spinning primitive webs or webs of a type from which the full-blown web might later evolve. The fact that during their "childhood" they had been fed by their keeper without any need for spinning had not affected their abilities! Another experiment was done in outer space in one of the National Aeronautics and Space Administration research satellites. Spiders were carried aboard to see if they could weave their webs in zero gravity. The answer was yes! Even without "reference information" that gravity provides, the spiders were still able to carry out their web-building instincts. So spiders inherit their web-weaving skills — the ability is preprogrammed.
Did Web-Weaving Evolve?
But how could such an elaborate and complicated scheme for web-building ever develop? Can you imagine the first spider trying in vain to catch insects in a "proto-web"? Most spiders don't spin webs at all, so you can hardly say they "had" to spin a web. Yet if they didn't "have to," then why spend all those "millions of years" (according to evolutionary theory) developing the ability? The whole process of designing and constructing a silk web is absolutely incredible — especially if you believe it all happened by chance and gradual evolution. Did the lowly spider learn the art and science of web-building on its own? "The orb web would seem to stand alone as a glorious creation, an incredible novelty designed by superior artisans!" writes Willis Gertsch, author of American Spiders. And according to another source: "The question of how the elaborate method of construction once was acquired by the ancestors of today's orb weavers is not easy to answer" ("Evolution of the Web," B. J. Kaston, Natural History, April 1966). It's certainly not an easy question to answer as long as you assume it all depended on the spider and random evolutionary changes. But, like many other marvels of creation, the amazing web wizardry of spiders can be readily understood as a fascinating example of the creative genius of the Creator God.