Nature's Weavers

New Zealand Herald, Volume LXXVI, Issue 23339, 6 May 1939, Page 10 (Supplement)

Nature's Weavers

By A. G. STEVENSON

ONCE upon a time there lived in Greece a maiden named Arachne. In the art of weaving and embroidery she excelled all others; but alas, she boasted endlessly of her prowess with loom and needle. In fact, she asserted that not even Athene, goddess of wisdom and patroness of the Arts, could rival her in her work. Hearing this, Athene arranged a test, in which, of course, Arachne was beaten, and as a result, attempted to hang herself. But Athene was not prepared to let her off so easily, so changed Arachno's suspended body into a spider in order that she should continue through the ages to spin and weave ceaselossly with silk drawn from her own body. Memory Perpetuated Such is the ancient Greek story of Arachne, and to this day men of science perpetuate the memory of this boastful young woman in the Arachnids, which they have bestowed upon tho order of creatures including the spider and its relations. Truly, in the art of weaving tho spider has no rival, and anyone who cares to look about at some of its handiwork cannot fail to be impressed with its skill and enterprise. With autumn come tho dews and fogs, revealing to us some of tho surprising ingenuity and enterprise of the often despised spider. The early morning sun shines on exquisitely bejewelled webs,

stretched like rich necklets of gems over shrubs and hedgerows. These symmetrical nets are constructed with such fine threads that they are practically invisible, and it is only when adorned with glistening dew-pearls that they are liable to .catch the. eye. ' • !,u '-a Engineering Skill

In the spider world, engineering skill and ingenuity have attained a standard of no mean order, and in the construction of her snares the spider seems to display a certain amount of judgment which could hardly be regarded as pure instinct. Each kind of spider has its own particular type of web, and the wheel-like not so often seen in the mornings is the work of the common orb-weaver of the gardens. Any evening we may be lucky enough to see the whole method of orb-weaving from start to finish, and we will be amazed at the speed and precision with which the work is carried out. Actually the whole process has been observed to take as little as 30 or 40 minutes in some cases; which certainly means that it has no time to lose in experiments. The construction is followed out methodically and unerringly, just as if it is working to some well-memorised plan. The first requirement in the construction of the web is a good strong ■ line to act as a main support. To establish this the spider takes up a suitable position and begins to pay out liquid silk from its manifold spinnerets. As soon as the silk leaves the spinnerets it is hardened by the air so that it becomes a single strong thread. •

Finding Anchorage * The loose end, which may be purposely frayed out to form a kind of kite, is borne away on the air, and the spider waits patiently until it knows by the pull on the line that it has found anchorage on some distant object. The

The Spider Has No Rieal

spider then takes up the slack, makes it fast and proceeds to strengthen the line by passing to and fro across it, adding new strands as it goes. Next it runs out supporting lines in various directions so that its Jine will withstand wind, rain, and the impact of insects. The foundation now being firmly established, the spider fixes upon a suitable point as centre and runs out numerous radial lines like the spokes of a wheel, and when these are all secured and tightened up a lew extra lines are put in to serve as strengthening and scaffolding for the important operation of laying the sticky threads which wil trap the spider's prey. The silk used for the many spirals of the web is formed of different material from that which comprises the framework. It is covered with a gummy substance which acts like birdlime, helping to ensnare its prey. This viscid thread is stretched out and attached to the radial lines with remarkable regularity as the spider swings from point to point, forming, when finished, a beautiful, even spiral. A small space is left in the' centre where the spider may rest without coming in contact with the sticky lines. Gummy Material Closer examination will show that the gummy substance on the lines forms itself into little beads, giving the magnified line the appearance of a string of pearls. These beads arc formed in quite a simple manner. Immediately before attaching the line to one of the radial cables the spider takes hold of

—The Humorist it with its foot and stretches it, then, fastening it down with its spinnerets, it lets it go and it springs into position. This stretching causes the gummy, material to form, itself into more or less, globular masses, which . filially assume their bead-like form. ' \j* , » The beads are very sticky, apd adhere to any insect that comes into contact with the net, holding it fast until the spider is able to come out and secure its prey. In the construction of an ordinary web of this description, as many as a thousand attachments have to be made, and when we consider that these have to be carefully spaced and the line stretched and tested each time, we cannot but marvel at the ingenuity and patience involved. , The web is now completed, and the spider retreats to its'bower to wait till some luckless insect becomes enmeshed in its snare. When this occurs, the spider is apprised of the fact- by the vibration of its net, whereupon it dashes out to truss up its victim in a shroud of silk and bear it back in triumph to its parlour. Repairing Damage If left undisturbed, such-a net may last for several days,, but more often than not it becomes severely damaged by wind and rain. In spite of this, the indefatigable spider will set to work to repair it every evening, and with the coming of the sun next morning it will present an appearance just as perfect as at first.

Before leaving this subject, it may be as well to mention that in Spiderland the females are the all-important members of the household. All the elaborate webs and snares are made by the females, all the great hunters are females, and the males play a very insignificant part. in fact, when a male makes up to the lady of his choice he does not know whether she will accept him or eat him, or both.