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THE GARDEN SPIDERS: BUILDING THE WEB




The fowling-snare is one of man's ingenious villainies. With lines, pegs
and poles, two large, earth-coloured nets are stretched upon the ground,
one to the right, the other to the left of a bare surface. A long cord,
pulled, at the right moment, by the fowler, who hides in a brushwood hut,
works them and brings them together suddenly, like a pair of shutters.

Divided between the two nets are the cages of the decoy-birds--Linnets
and Chaffinches, Greenfinches and Yellowhammers, Buntings and
Ortolans--sharp-eared creatures which, on perceiving the distant passage
of a flock of their own kind, forthwith utter a short calling note. One
of them, the _Sambe_, an irresistible tempter, hops about and flaps his
wings in apparent freedom. A bit of twine fastens him to his convict's
stake. When, worn with fatigue and driven desperate by his vain attempts
to get away, the sufferer lies down flat and refuses to do his duty, the
fowler is able to stimulate him without stirring from his hut. A long
string sets in motion a little lever working on a pivot. Raised from the
ground by this diabolical contrivance, the bird flies, falls down and
flies up again at each jerk of the cord.

The fowler waits, in the mild sunlight of the autumn morning. Suddenly,
great excitement in the cages. The Chaffinches chirp their rallying-cry:

'Pinck! Pinck!'

There is something happening in the sky. The _Sambe_, quick! They are
coming, the simpletons; they swoop down upon the treacherous floor. With
a rapid movement, the man in ambush pulls his string. The nets close and
the whole flock is caught.

Man has wild beast's blood in his veins. The fowler hastens to the
slaughter. With his thumb, he stifles the beating of the captives'
hearts, staves in their skulls. The little birds, so many piteous heads
of game, will go to market, strung in dozens on a wire passed through
their nostrils.

For scoundrelly ingenuity the Epeira's net can bear comparison with the
fowler's; it even surpasses it when, on patient study, the main features
of its supreme perfection stand revealed. What refinement of art for a
mess of Flies! Nowhere, in the whole animal kingdom, has the need to eat
inspired a more cunning industry. If the reader will meditate upon the
description that follows, he will certainly share my admiration.

First of all, we must witness the making of the net; we must see it
constructed and see it again and again, for the plan of such a complex
work can only be grasped in fragments. To-day, observation will give us
one detail; to-morrow, it will give us a second, suggesting fresh points
of view; as our visits multiply, a new fact is each time added to the sum
total of the acquired data, confirming those which come before or
directing our thoughts along unsuspected paths.

The snow-ball rolling over the carpet of white grows enormous, however
scanty each fresh layer be. Even so with truth in observational science:
it is built up of trifles patiently gathered together. And, while the
collecting of these trifles means that the student of Spider industry
must not be chary of his time, at least it involves no distant and
speculative research. The smallest garden contains Epeirae, all
accomplished weavers.

In my enclosure, which I have stocked carefully with the most famous
breeds, I have six different species under observation, all of a useful
size, all first-class spinners. Their names are the Banded Epeira
(_Epeira fasciata_, WALCK.), the Silky Epeira (_E. sericea_, WALCK.), the
Angular Epeira (_E. angulata_, WALCK.), the Pale-tinted Epeira (_E.
pallida_, OLIV.), the Diadem Epeira, or Cross Spider (_E. diadema_,
CLERK.), and the Crater Epeira (_E. cratera_, WALCK.).

I am able, at the proper hours, all through the fine season, to question
them, to watch them at work, now this one, anon that, according to the
chances of the day. What I did not see very plainly yesterday I can see
the next day, under better conditions, and on any of the following days,
until the phenomenon under observation is revealed in all clearness.

Let us go every evening, step by step, from one border of tall rosemaries
to the next. Should things move too slowly, we will sit down at the foot
of the shrubs, opposite the rope-yard, where the light falls favourably,
and watch with unwearying attention. Each trip will be good for a fact
that fills some gap in the ideas already gathered. To appoint one's
self, in this way, an inspector of Spiders' webs, for many years in
succession and for long seasons, means joining a not overcrowded
profession, I admit. Heaven knows, it does not enable one to put money
by! No matter: the meditative mind returns from that school fully
satisfied.

To describe the separate progress of the work in the case of each of the
six Epeirae mentioned would be a useless repetition: all six employ the
same methods and weave similar webs, save for certain details that shall
be set forth later. I will, therefore, sum up in the aggregate the
particulars supplied by one or other of them.

My subjects, in the first instance, are young and boast but a slight
corporation, very far removed from what it will be in the late autumn.
The belly, the wallet containing the rope-works, hardly exceeds a
peppercorn in bulk. This slenderness on the part of the spinstresses
must not prejudice us against their work: there is no parity between
their skill and their years. The adult Spiders, with their disgraceful
paunches, can do no better.

Moreover, the beginners have one very precious advantage for the
observer: they work by day, work even in the sun, whereas the old ones
weave only at night, at unseasonable hours. The first show us the
secrets of their looms without much difficulty; the others conceal them
from us. Work starts in July, a couple of hours before sunset.

The spinstresses of my enclosure then leave their daytime hiding-places,
select their posts and begin to spin, one here, another there. There are
many of them; we can choose where we please. Let us stop in front of
this one, whom we surprise in the act of laying the foundations of the
structure. Without any appreciable order, she runs about the rosemary-
hedge, from the tip of one branch to another within the limits of some
eighteen inches. Gradually, she puts a thread in position, drawing it
from her wire-mill with the combs attached to her hind-legs. This
preparatory work presents no appearance of a concerted plan. The Spider
comes and goes impetuously, as though at random; she goes up, comes down,
goes up again, dives down again and each time strengthens the points of
contact with intricate moorings distributed here and there. The result
is a scanty and disordered scaffolding.

Is disordered the word? Perhaps not. The Epeira's eye, more experienced
in matters of this sort than mine, has recognized the general lie of the
land; and the rope-fabric has been erected accordingly: it is very
inaccurate in my opinion, but very suitable for the Spider's designs.
What is it that she really wants? A solid frame to contain the network
of the web. The shapeless structure which she has just built fulfils the
desired conditions: it marks out a flat, free and perpendicular area.
This is all that is necessary.

The whole work, for that matter, is now soon completed; it is done all
over again, each evening, from top to bottom, for the incidents of the
chase destroy it in a night. The net is as yet too delicate to resist
the desperate struggles of the captured prey. On the other hand, the
adults' net, which is formed of stouter threads, is adapted to last some
time; and the Epeira gives it a more carefully-constructed framework, as
we shall see elsewhere.

A special thread, the foundation of the real net, is stretched across the
area so capriciously circumscribed. It is distinguished from the others
by its isolation, its position at a distance from any twig that might
interfere with its swaying length. It never fails to have, in the
middle, a thick white point, formed of a little silk cushion. This is
the beacon that marks the centre of the future edifice, the post that
will guide the Epeira and bring order into the wilderness of twists and
turns.

The time has come to weave the hunting-snare. The Spider starts from the
centre, which bears the white signpost, and, running along the
transversal thread, hurriedly reaches the circumference, that is to say,
the irregular frame enclosing the free space. Still with the same sudden
movement, she rushes from the circumference to the centre; she starts
again backwards and forwards, makes for the right, the left, the top, the
bottom; she hoists herself up, dives down, climbs up again, runs down and
always returns to the central landmark by roads that slant in the most
unexpected manner. Each time, a radius or spoke is laid, here, there, or
elsewhere, in what looks like mad disorder.

The operation is so erratically conducted that it takes the most
unremitting attention to follow it at all. The Spider reaches the margin
of the area by one of the spokes already placed. She goes along this
margin for some distance from the point at which she landed, fixes her
thread to the frame and returns to the centre by the same road which she
has just taken.

The thread obtained on the way in a broken line, partly on the radius and
partly on the frame, is too long for the exact distance between the
circumference and the central point. On returning to this point, the
Spider adjusts her thread, stretches it to the correct length, fixes it
and collects what remains on the central signpost. In the case of each
radius laid, the surplus is treated in the same fashion, so that the
signpost continues to increase in size. It was first a speck; it is now
a little pellet, or even a small cushion of a certain breadth.

We shall see presently what becomes of this cushion whereon the Spider,
that niggardly housewife, lays her saved-up bits of thread; for the
moment, we will note that the Epeira works it up with her legs after
placing each spoke, teazles it with her claws, mats it into felt with
noteworthy diligence. In so doing, she gives the spokes a solid common
support, something like the hub of our carriage-wheels.

The eventual regularity of the work suggests that the radii are spun in
the same order in which they figure in the web, each following
immediately upon its next neighbour. Matters pass in another manner,
which at first looks like disorder, but which is really a judicious
contrivance. After setting a few spokes in one direction, the Epeira
runs across to the other side to draw some in the opposite direction.
These sudden changes of course are highly logical; they show us how
proficient the Spider is in the mechanics of rope-construction. Were
they to succeed one another regularly, the spokes of one group, having
nothing as yet to counteract them, would distort the work by their
straining, would even destroy it for lack of a stabler support. Before
continuing, it is necessary to lay a converse group which will maintain
the whole by its resistance. Any combination of forces acting in one
direction must be forthwith neutralized by another in the opposite
direction. This is what our statics teach us and what the Spider puts
into practice; she is a past mistress of the secrets of rope-building,
without serving an apprenticeship.

One would think that this interrupted and apparently disordered labour
must result in a confused piece of work. Wrong: the rays are equidistant
and form a beautifully-regular orb. Their number is a characteristic
mark of the different species. The Angular Epeira places 21 in her web,
the Banded Epeira 32, the Silky Epeira 42. These numbers are not
absolutely fixed; but the variation is very slight.

Now which of us would undertake, off-hand, without much preliminary
experiment and without measuring-instruments, to divide a circle into a
given quantity of sectors of equal width? The Epeirae, though weighted
with a wallet and tottering on threads shaken by the wind, effect the
delicate division without stopping to think. They achieve it by a method
which seems mad according to our notions of geometry. Out of disorder
they evolve order.

We must not, however, give them more than their due. The angles are only
approximately equal; they satisfy the demands of the eye, but cannot
stand the test of strict measurement. Mathematical precision would be
superfluous here. No matter, we are amazed at the result obtained. How
does the Epeira come to succeed with her difficult problem, so strangely
managed? I am still asking myself the question.

The laying of the radii is finished. The Spider takes her place in the
centre, on the little cushion formed of the inaugural signpost and the
bits of thread left over. Stationed on this support, she slowly turns
round and round. She is engaged on a delicate piece of work. With an
extremely thin thread, she describes from spoke to spoke, starting from
the centre, a spiral line with very close coils. The central space thus
worked attains, in the adults' webs, the dimensions of the palm of one's
hand; in the younger Spiders' webs, it is much smaller, but it is never
absent. For reasons which I will explain in the course of this study, I
shall call it, in future, the 'resting-floor.'

The thread now becomes thicker. The first could hardly be seen; the
second is plainly visible. The Spider shifts her position with great
slanting strides, turns a few times, moving farther and farther from the
centre, fixes her line each time to the spoke which she crosses and at
last comes to a stop at the lower edge of the frame. She has described a
spiral with coils of rapidly-increasing width. The average distance
between the coils, even in the structures of the young Epeirae, is one
centimetre. {29}

Let us not be misled by the word 'spiral,' which conveys the notion of a
curved line. All curves are banished from the Spiders' work; nothing is
used but the straight line and its combinations. All that is aimed at is
a polygonal line drawn in a curve as geometry understands it. To this
polygonal line, a work destined to disappear as the real toils are woven,
I will give the name of the 'auxiliary spiral.' Its object is to supply
cross-bars, supporting rungs, especially in the outer zone, where the
radii are too distant from one another to afford a suitable groundwork.
Its object is also to guide the Epeira in the extremely delicate business
which she is now about to undertake.

But, before that, one last task becomes essential. The area occupied by
the spokes is very irregular, being marked out by the supports of the
branch, which are infinitely variable. There are angular niches which,
if skirted too closely, would disturb the symmetry of the web about to be
constructed. The Epeira needs an exact space wherein gradually to lay
her spiral thread. Moreover, she must not leave any gaps through which
her prey might find an outlet.

An expert in these matters, the Spider soon knows the corners that have
to be filled up. With an alternating movement, first in this direction,
then in that, she lays, upon the support of the radii, a thread that
forms two acute angles at the lateral boundaries of the faulty part and
describes a zigzag line not wholly unlike the ornament known as the fret.

The sharp corners have now been filled with frets on every side; the time
has come to work at the essential part, the snaring-web for which all the
rest is but a support. Clinging on the one hand to the radii, on the
other to the chords of the auxiliary spiral, the Epeira covers the same
ground as when laying the spiral, but in the opposite direction:
formerly, she moved away from the centre; now she moves towards it and
with closer and more numerous circles. She starts from the base of the
auxiliary spiral, near the frame.

What follows is difficult to observe, for the movements are very quick
and spasmodic, consisting of a series of sudden little rushes, sways and
bends that bewilder the eye. It needs continuous attention and repeated
examination to distinguish the progress of the work however slightly.

The two hind-legs, the weaving implements, keep going constantly. Let us
name them according to their position on the work-floor. I call the leg
that faces the centre of the coil, when the animal moves, the 'inner
leg;' the one outside the coil the 'outer leg.'

The latter draws the thread from the spinneret and passes it to the inner
leg, which, with a graceful movement, lays it on the radius crossed. At
the same time, the first leg measures the distance; it grips the last
coil placed in position and brings within a suitable range that point of
the radius whereto the thread is to be fixed. As soon as the radius is
touched, the thread sticks to it by its own glue. There are no slow
operations, no knots: the fixing is done of itself.

Meanwhile, turning by narrow degrees, the spinstress approaches the
auxiliary chords that have just served as her support. When, in the end,
these chords become too close, they will have to go; they would impair
the symmetry of the work. The Spider, therefore, clutches and holds on
to the rungs of a higher row; she picks up, one by one, as she goes
along, those which are of no more use to her and gathers them into a fine-
spun ball at the contact-point of the next spoke. Hence arises a series
of silky atoms marking the course of the disappearing spiral.

The light has to fall favourably for us to perceive these specks, the
only remains of the ruined auxiliary thread. One would take them for
grains of dust, if the faultless regularity of their distribution did not
remind us of the vanished spiral. They continue, still visible, until
the final collapse of the net.

And the Spider, without a stop of any kind, turns and turns and turns,
drawing nearer to the centre and repeating the operation of fixing her
thread at each spoke which she crosses. A good half-hour, an hour even
among the full-grown Spiders, is spent on spiral circles, to the number
of about fifty for the web of the Silky Epeira and thirty for those of
the Banded and the Angular Epeira.

At last, at some distance from the centre, on the borders of what I have
called the resting-floor, the Spider abruptly terminates her spiral when
the space would still allow of a certain number of turns. We shall see
the reason of this sudden stop presently. Next, the Epeira, no matter
which, young or old, hurriedly flings herself upon the little central
cushion, pulls it out and rolls it into a ball which I expected to see
thrown away. But no: her thrifty nature does not permit this waste. She
eats the cushion, at first an inaugural landmark, then a heap of bits of
thread; she once more melts in the digestive crucible what is no doubt
intended to be restored to the silken treasury. It is a tough mouthful,
difficult for the stomach to elaborate; still, it is precious and must
not be lost. The work finishes with the swallowing. Then and there, the
Spider instals herself, head downwards, at her hunting-post in the centre
of the web.

The operation which we have just seen gives rise to a reflection. Men
are born right-handed. Thanks to a lack of symmetry that has never been
explained, our right side is stronger and readier in its movements than
our left. The inequality is especially noticeable in the two hands. Our
language expresses this supremacy of the favoured side in the terms
dexterity, adroitness and address, all of which allude to the right hand.

Is the animal, on its side, right-handed, left-handed, or unbiased? We
have had opportunities of showing that the Cricket, the Grasshopper and
many others draw their bow, which is on the right wing-case, over the
sounding apparatus, which is on the left wing-case. They are
right-handed.

When you and I take an unpremeditated turn, we spin round on our right
heel. The left side, the weaker, moves on the pivot of the right, the
stronger. In the same way, nearly all the Molluscs that have spiral
shells roll their coils from left to right. Among the numerous species
in both land and water fauna, only a very few are exceptional and turn
from right to left.

It would be interesting to try and work out to what extent that part of
the zoological kingdom which boasts a two-sided structure is divided into
right-handed and left-handed animals. Can dissymetry, that source of
contrasts, be a general rule? Or are there neutrals, endowed with equal
powers of skill and energy on both sides? Yes, there are; and the Spider
is one of them. She enjoys the very enviable privilege of possessing a
left side which is no less capable than the right. She is ambidextrous,
as witness the following observations.

When laying her snaring-thread, every Epeira turns in either direction
indifferently, as a close watch will prove. Reasons whose secret escapes
us determine the direction adopted. Once this or the other course is
taken, the spinstress does not change it, even after incidents that
sometimes occur to disturb the progress of the work. It may happen that
a Gnat gets caught in the part already woven. The Spider thereupon
abruptly interrupts her labours, hastens up to the prey, binds it and
then returns to where she stopped and continues the spiral in the same
order as before.

At the commencement of the work, gyration in one direction being employed
as well as gyration in the other, we see that, when making her repeated
webs, the same Epeira turns now her right side, now her left to the
centre of the coil. Well, as we have said, it is always with the inner
hind-leg, the leg nearer the centre, that is to say, in some cases the
right and in some cases the left leg, that she places the thread in
position, an exceedingly delicate operation calling for the display of
exquisite skill, because of the quickness of the action and the need for
preserving strictly equal distances. Any one seeing this leg working
with such extreme precision, the right leg to-day, the left to-morrow,
becomes convinced that the Epeira is highly ambidextrous.





Next: THE GARDEN SPIDERS: MY NEIGHBOUR

Previous: THE CRAB SPIDER



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