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CHAPTER VI: THE NARBONNE LYCOSA: THE
CLIMBING-INSTINCT
The month of March comes to an end; and the
departure of the youngsters
begins, in glorious weather, during the hottest
hours of the morning.
Laden with her swarming burden, the mother Lycosa is
outside her burrow,
squatting on the parapet at the entrance. She lets them
do as they
please; as though indifferent to what is happening, she exhibits
neither
encouragement nor regret. Whoso will goes; whoso will remains
behind.
First these, then those, according as they feel themselves duly
soaked
with sunshine, the little ones leave the mother in batches, run about
for
a moment on the ground and then quickly reach the trellis-work of
the
cage, which they climb with surprising alacrity. They pass through
the
meshes, they clamber right to the top of the citadel. All, with not
one
exception, make for the heights, instead of roaming on the ground,
as
might reasonably be expected from the eminently earthly habits of
the
Lycosae; all ascend the dome, a strange procedure whereof I do not
yet
guess the object.
I receive a hint from the upright ring that
finishes the top of the cage.
The youngsters hurry to it. It represents the
porch of their gymnasium.
They hang out threads across the opening; they
stretch others from the
ring to the nearest points of the trellis-work. On
these foot-bridges,
they perform slack-rope exercises amid endless comings
and goings. The
tiny legs open out from time to time and straddle as though
to reach the
most distant points. I begin to realize that they are acrobats
aiming at
loftier heights than those of the dome.
I top the trellis
with a branch that doubles the attainable height. The
bustling crowd hastily
scrambles up it, reaches the tip of the topmost
twigs and thence sends out
threads that attach themselves to every
surrounding object. These form so
many suspension-bridges; and my
beasties nimbly run along them, incessantly
passing to and fro. One
would say that they wished to climb higher still. I
will endeavour to
satisfy their desires.
I take a nine-foot reed, with
tiny branches spreading right up to the
top, and place it above the
cage. The little Lycosae clamber to the very
summit. Here, longer threads
are produced from the rope-yard and are now
left to float, anon converted
into bridges by the mere contact of the
free end with the neighbouring
supports. The rope-dancers embark upon
them and form garlands which the
least breath of air swings daintily. The
thread is invisible when it does
not come between the eyes and the sun;
and the whole suggests rows of Gnats
dancing an aerial ballet.
Then, suddenly, teased by the air-currents, the
delicate mooring breaks
and flies through space. Behold the emigrants off
and away, clinging to
their thread. If the wind be favourable, they can land
at great
distances. Their departure is thus continued for a week or two, in
bands
more or less numerous, according to the temperature and the brightness
of
the day. If the sky be overcast, none dreams of leaving. The
travellers
need the kisses of the sun, which give energy and
vigour.
At last, the whole family has disappeared, carried afar by its
flying-
ropes. The mother remains alone. The loss of her offspring hardly
seems
to distress her. She retains her usual colour and plumpness, which is
a
sign that the maternal exertions have not been too much for her.
I
also notice an increased fervour in the chase. While burdened with
her
family, she was remarkably abstemious, accepting only with great
reserve
the game placed at her disposal. The coldness of the season may
have
militated against copious refections; perhaps also the weight of
the
little ones hampered her movements and made her more discreet
in
attacking the prey.
To-day, cheered by the fine weather and able to
move freely, she hurries
up from her lair each time I set a tit-bit to her
liking buzzing at the
entrance to her burrow; she comes and takes from my
fingers the savoury
Locust, the portly Anoxia; {26} and this performance is
repeated daily,
whenever I have the leisure to devote to it. After a frugal
winter, the
time has come for plentiful repasts.
This appetite tells
us that the animal is not at the point of death; one
does not feast in this
way with a played-out stomach. My boarders are
entering in full vigour upon
their fourth year. In the winter, in the
fields, I used to find large
mothers, carting their young, and others not
much more than half their
size. The whole series, therefore, represented
three generations. And now,
in my earthenware pans, after the departure
of the family, the old matrons
still carry on and continue as strong as
ever. Every outward appearance
tells us that, after becoming
great-grandmothers, they still keep themselves
fit for propagating their
species.
The facts correspond with these
anticipations. When September returns,
my captives are dragging a bag as
bulky as that of last year. For a long
time, even when the eggs of the
others have been hatched for some weeks
past, the mothers come daily to the
threshold of the burrow and hold out
their wallets for incubation by the
sun. Their perseverance is not
rewarded: nothing issues from the satin
purse; nothing stirs within. Why?
Because, in the prison of my cages, the
eggs have had no father. Tired
of waiting and at last recognizing the
barrenness of their produce, they
push the bag of eggs outside the burrow and
trouble about it no more. At
the return of spring, by which time the family,
if developed according to
rule, would have been emancipated, they die. The
mighty Spider of the
waste-lands, therefore, attains to an even more
patriarchal age than her
neighbour the Sacred Beetle: {27} she lives for five
years at the very
least.
Let us leave the mothers to their business
and return to the youngsters.
It is not without a certain surprise that we
see the little Lycosae, at
the first moment of their emancipation, hasten to
ascend the heights.
Destined to live on the ground, amidst the short grass,
and afterwards to
settle in the permanent abode, a pit, they start by being
enthusiastic
acrobats. Before descending to the low levels, their normal
dwelling-
place, they affect lofty altitudes.
To rise higher and ever
higher is their first need. I have not, it
seems, exhausted the limit of
their climbing-instinct even with a nine-
foot pole, suitably furnished with
branches to facilitate the escalade.
Those who have eagerly reached the very
top wave their legs, fumble in
space as though for yet higher stalks. It
behoves us to begin again and
under better conditions.
Although the
Narbonne Lycosa, with her temporary yearning for the
heights, is more
interesting than other Spiders, by reason of the fact
that her usual
habitation is underground, she is not so striking at
swarming-time, because
the youngsters, instead of all migrating at once,
leave the mother at
different periods and in small batches. The sight
will be a finer one with
the common Garden or Cross Spider, the Diadem
Epeira (_Epeira diadema_,
LIN.), decorated with three white crosses on
her back.
She lays her
eggs in November and dies with the first cold snap. She is
denied the
Lycosa's longevity. She leaves the natal wallet early one
spring and never
sees the following spring. This wallet, which contains
the eggs, has none of
the ingenious structure which we admired in the
Banded and in the Silky
Epeira. No longer do we see a graceful balloon-
shape nor yet a paraboloid
with a starry base; no longer a tough,
waterproof satin stuff; no longer a
swan's-down resembling a fleecy,
russet cloud; no longer an inner keg in
which the eggs are packed. The
art of stout fabrics and of walls within
walls is unknown here.
The work of the Cross Spider is a pill of white
silk, wrought into a
yielding felt, through which the new-born Spiders will
easily work their
way, without the aid of the mother, long since dead, and
without having
to rely upon its bursting at the given hour. It is about the
size of a
damson.
We can judge the method of manufacture from the
structure. Like the
Lycosa, whom we saw, in Chapter III., at work in one of
my earthenware
pans, the Cross Spider, on the support supplied by a few
threads
stretched between the nearest objects, begins by making a shallow
saucer
of sufficient thickness to dispense with subsequent
corrections. The
process is easily guessed. The tip of the abdomen goes up
and down, down
and up with an even beat, while the worker shifts her place a
little.
Each time, the spinnerets add a bit of thread to the carpet already
made.
When the requisite thickness is obtained, the mother empties her
ovaries,
in one continuous flow, into the centre of the bowl. Glued together
by
their inherent moisture, the eggs, of a handsome orange-yellow, form
a
ball-shaped heap. The work of the spinnerets is resumed. The ball
of
germs is covered with a silk cap, fashioned in the same way as
the
saucer. The two halves of the work are so well joined that the
whole
constitutes an unbroken sphere.
The Banded Epeira and the Silky
Epeira, those experts in the manufacture
of rainproof textures, lay their
eggs high up, on brushwood and bramble,
without shelter of any kind. The
thick material of the wallets is enough
to protect the eggs from the
inclemencies of the winter, especially from
damp. The Diadem Epeira, or
Cross Spider, needs a cranny for hers, which
is contained in a non-waterproof
felt. In a heap of stones, well exposed
to the sun, she will choose a large
slab to serve as a roof. She lodges
her pill underneath it, in the company
of the hibernating Snail.
More often still, she prefers the thick tangle
of some dwarf shrub,
standing eight or nine inches high and retaining its
leaves in winter. In
the absence of anything better, a tuft of grass answers
the purpose.
Whatever the hiding-place, the bag of eggs is always near the
ground,
tucked away as well as may be, amid the surrounding
twigs.
Save in the case of the roof supplied by a large stone, we see
that the
site selected hardly satisfies proper hygienic needs. The Epeira
seems
to realize this fact. By way of an additional protection, even under
a
stone, she never fails to make a thatched roof for her eggs. She
builds
them a covering with bits of fine, dry grass, joined together with
a
little silk. The abode of the eggs becomes a straw wigwam.
Good
luck procures me two Cross Spiders' nests, on the edge of one of the
paths in
the enclosure, among some tufts of ground-cypress, or lavender-
cotton. This
is just what I wanted for my plans. The find is all the
more valuable as the
period of the exodus is near at hand.
I prepare two lengths of bamboo,
standing about fifteen feet high and
clustered with little twigs from top to
bottom. I plant one of them
straight up in the tuft, beside the first
nest. I clear the surrounding
ground, because the bushy vegetation might
easily, thanks to threads
carried by the wind, divert the emigrants from the
road which I have laid
out for them. The other bamboo I set up in the middle
of the yard, all
by itself, some few steps from any outstanding object. The
second nest
is removed as it is, shrub and all, and placed at the bottom of
the tall,
ragged distaff.
The events expected are not long in
coming. In the first fortnight in
May, a little earlier in one case, a
little later in the other, the two
families, each presented with a bamboo
climbing-pole, leave their
respective wallets. There is nothing remarkable
about the mode of
egress. The precincts to be crossed consist of a very
slack net-work,
through which the outcomers wriggle: weak little
orange-yellow beasties,
with a triangular black patch upon their sterns. One
morning is long
enough for the whole family to make its appearance.
By
degrees, the emancipated youngsters climb the nearest twigs, clamber
to the
top, and spread a few threads. Soon, they gather in a compact,
ball-shaped
cluster, the size of a walnut. They remain motionless. With
their heads
plunged into the heap and their sterns projecting, they doze
gently,
mellowing under the kisses of the sun. Rich in the possession of
a thread in
their belly as their sole inheritance, they prepare to
disperse over the wide
world.
Let us create a disturbance among the globular group by stirring
it with
a straw. All wake up at once. The cluster softly dilates and
spreads,
as though set in motion by some centrifugal force; it becomes
a
transparent orb wherein thousands and thousands of tiny legs quiver
and
shake, while threads are extended along the way to be
followed. The
whole work resolves itself into a delicate veil which swallows
up the
scattered family. We then see an exquisite nebula against
whose
opalescent tapestry the tiny animals gleam like twinkling orange
stars.
This straggling state, though it last for hours, is but
temporary. If
the air grow cooler, if rain threaten, the spherical group
reforms at
once. This is a protective measure. On the morning after a
shower, I
find the families on either bamboo in as good condition as on the
day
before. The silk veil and the pill formation have sheltered them
well
enough from the downpour. Even so do Sheep, when caught in a storm
in
the pastures, gather close, huddle together and make a common rampart
of
their backs.
The assembly into a ball-shaped mass is also the rule
in calm, bright
weather, after the morning's exertions. In the afternoon,
the climbers
collect at a higher point, where they weave a wide, conical
tent, with
the end of a shoot for its top, and, gathered into a compact
group, spend
the night there. Next day, when the heat returns, the ascent is
resumed
in long files, following the shrouds which a few pioneers have rigged
and
which those who come after elaborate with their own
work.
Collected nightly into a globular troop and sheltered under a fresh
tent,
for three or four days, each morning, before the sun grows too hot,
my
little emigrants thus raise themselves, stage by stage, on both
bamboos,
until they reach the sun-unit, at fifteen feet above the
ground. The
climb comes to an end for lack of foothold.
Under normal
conditions, the ascent would be shorter. The young Spiders
have at their
disposal the bushes, the brushwood, providing supports on
every side for the
threads wafted hither and thither by the eddying air-
currents. With these
rope-bridges flung across space, the dispersal
presents no
difficulties. Each emigrant leaves at his own good time and
travels as suits
him best.
My devices have changed these conditions somewhat. My two
bristling
poles stand at a distance from the surrounding shrubs, especially
the one
which I planted in the middle of the yard. Bridges are out of
the
question, for the threads flung into the air are not long enough. And
so
the acrobats, eager to get away, keep on climbing, never come down
again,
are impelled to seek in a higher position what they have failed to
find
in a lower. The top of my two bamboos probably fails to represent
the
limit of what my keen climbers are capable of achieving.
We shall
see, in a moment, the object of this climbing-propensity, which
is a
sufficiently remarkable instinct in the Garden Spiders, who have as
their
domain the low-growing brushwood wherein their nets are spread; it
becomes a
still more remarkable instinct in the Lycosa, who, except at
the moment when
she leaves her mother's back, never quits the ground and
yet, in the early
hours of her life, shows herself as ardent a wooer of
high places as the
young Garden Spiders.
Let us consider the Lycosa in particular. In her,
at the moment of the
exodus, a sudden instinct arises, to disappear, as
promptly and for ever,
a few hours later. This is the climbing-instinct,
which is unknown to
the adult and soon forgotten by the emancipated
youngling, doomed to
wander homeless, for many a long day, upon the
ground. Neither of them
dreams of climbing to the top of a grass-stalk. The
full-grown Spider
hunts trapper-fashion, ambushed in her tower; the young one
hunts afoot
through the scrubby grass. In both cases there is no web and
therefore
no need for lofty contact-points. They are not allowed to quit
the
ground and climb the heights.
Yet here we have the young Lycosa,
wishing to leave the maternal abode
and to travel far afield by the easiest
and swiftest methods, suddenly
becoming an enthusiastic climber. Impetuously
she scales the wire
trellis of the cage where she was born; hurriedly she
clambers to the top
of the tall mast which I have prepared for her. In the
same way, she
would make for the summit of the bushes in her
waste-land.
We catch a glimpse of her object. From on high, finding a
wide space
beneath her, she sends a thread floating. It is caught by the
wind and
carries her hanging to it. We have our aeroplanes; she too
possesses her
flying-machine. Once the journey is accomplished, naught
remains of this
ingenious business. The climbing-instinct conies suddenly,
at the hour
of need, and no less suddenly
vanishes.
CHAPTER VII: THE SPIDERS' EXODUS
Seeds,
when ripened in the fruit, are disseminated, that is to say,
scattered on the
surface of the ground, to sprout in spots as yet
unoccupied and fill the
expanses that realize favourable conditions.
Amid the wayside rubbish
grows one of the gourd family, _Ecbalium
elaterium_, commonly called the
squirting cucumber, whose fruit--a rough
and extremely bitter little
cucumber--is the size of a date. When ripe,
the fleshy core resolves into a
liquid in which float the seeds.
Compressed by the elastic rind of the fruit,
this liquid bears upon the
base of the footstalk, which is gradually forced
out, yields like a
stopper, breaks off and leaves an orifice through which a
stream of seeds
and fluid pulp is suddenly ejected. If, with a novice hand,
under a
scorching sun, you shake the plant laden with yellow fruit, you are
bound
to be somewhat startled when you hear a noise among the leaves
and
receive the cucumber's grapeshot in your face.
The fruit of the
garden balsam, when ripe, splits, at the least touch,
into five fleshy
valves, which curl up and shoot their seeds to a
distance. The botanical
name of _Impatiens_ given to the balsam alludes
to this sudden dehiscence of
the capsules, which cannot endure contact
without bursting.
In the
damp and shady places of the woods there exists a plant of the
same family
which, for similar reasons, bears the even more expressive
name of _Impatiens
noli-me-tangere_, or touch-me-not.
The capsule of the pansy expands into
three valves, each scooped out like
a boat and laden in the middle with two
rows of seeds. When these valves
dry, the edges shrivel, press upon the
grains and eject them.
Light seeds, especially those of the order of
Compositae, have aeronautic
apparatus--tufts, plumes, fly-wheels--which keep
them up in the air and
enable them to take distant voyages. In this way, at
the least breath,
the seeds of the dandelion, surmounted by a tuft of
feathers, fly from
their dry receptacle and waft gently in the
air.
Next to the tuft, the wing is the most satisfactory contrivance
for
dissemination by wind. Thanks to their membranous edge, which gives
them
the appearance of thin scales, the seeds of the yellow wall-flower
reach
high cornices of buildings, clefts of inaccessible rocks, crannies in
old
walls, and sprout in the remnant of mould bequeathed by the mosses
that
were there before them.
The samaras, or keys, of the elm, formed
of a broad, light fan with the
seed cased in its centre; those of the maple,
joined in pairs and
resembling the unfurled wings of a bird; those of the
ash, carved like
the blade of an oar, perform the most distant journeys when
driven before
the storm.
Like the plant, the insect also sometimes
possesses travelling-apparatus,
means of dissemination that allow large
families to disperse quickly over
the country, so that each member may have
his place in the sun without
injuring his neighbour; and these apparatus,
these methods vie in
ingenuity with the elm's samara, the dandelion-plume and
the catapult of
the squirting cucumber.
Let us consider, in
particular, the Epeirae, those magnificent Spiders
who, to catch their prey,
stretch, between one bush and the next, great
vertical sheets of meshes,
resembling those of the fowler. The most
remarkable in my district is the
Banded Epeira (_Epeira fasciata_,
WALCK.), so prettily belted with yellow,
black and silvery white. Her
nest, a marvel of gracefulness, is a satin bag,
shaped like a tiny pear.
Its neck ends in a concave mouthpiece closed with a
lid, also of satin.
Brown ribbons, in fanciful meridian waves, adorn the
object from pole to
pole.
Open the nest. We have seen, in an earlier
chapter, {28} what we find
there; let us retell the story. Under the outer
wrapper, which is as
stout as our woven stuffs and, moreover, perfectly
waterproof, is a
russet eiderdown of exquisite delicacy, a silky fluff
resembling driven
smoke. Nowhere does mother-love prepare a softer
bed.
In the middle of this downy mass hangs a fine, silk,
thimble-shaped
purse, closed with a movable lid. This contains the eggs, of
a pretty
orange-yellow and about five hundred in number.
All things
considered, is not this charming edifice an animal fruit, a
germ-casket, a
capsule to be compared with that of the plants? Only, the
Epeira's wallet,
instead of seeds, holds eggs. The difference is more
apparent than real, for
egg and grain are one.
How will this living fruit, ripening in the heat
beloved of the Cicadae,
manage to burst? How, above all, will dissemination
take place? They
are there in their hundreds. They must separate, go far
away, isolate
themselves in a spot where there is not too much fear of
competition
among neighbours. How will they set to work to achieve this
distant
exodus, weaklings that they are, taking such very tiny
steps?
I receive the first answer from another and much earlier Epeira,
whose
family I find, at the beginning of May, on a yucca in the
enclosure. The
plant blossomed last year. The branching flower-stem, some
three feet
high, still stands erect, though withered. On the green leaves,
shaped
like a sword-blade, swarm two newly-hatched families. The wee
beasties
are a dull yellow, with a triangular black patch upon their
stern. Later
on, three white crosses, ornamenting the back, will tell me
that my find
corresponds with the Cross or Diadem Spider (_Epeira diadema_,
WALCK.).
When the sun reaches this part of the enclosure, one of the two
groups
falls into a great state of flutter. Nimble acrobats that they are,
the
little Spiders scramble up, one after the other, and reach the top of
the
stem. Here, marches and countermarches, tumult and confusion reign,
for
there is a slight breeze which throws the troop into disorder. I see
no
connected manoeuvres. From the top of the stalk they set out at
every
moment, one by one; they dart off suddenly; they fly away, so to
speak.
It is as though they had the wings of a Gnat.
Forthwith they
disappear from view. Nothing that my eyes can see
explains this strange
flight; for precise observation is impossible amid
the disturbing influences
out of doors. What is wanted is a peaceful
atmosphere and the quiet of my
study.
I gather the family in a large box, which I close at once, and
instal it
in the animals' laboratory, on a small table, two steps from the
open
window. Apprised by what I have just seen of their propensity to
resort
to the heights, I give my subjects a bundle of twigs, eighteen
inches
tall, as a climbing-pole. The whole band hurriedly clambers up
and
reaches the top. In a few moments there is not one lacking in the
group
on high. The future will tell us the reason of this assemblage on
the
projecting tips of the twigs.
The little Spiders are now spinning
here and there at random: they go up,
go down, come up again. Thus is woven
a light veil of divergent threads,
a many-cornered web with the end of the
branch for its summit and the
edge of the table for its base, some eighteen
inches wide. This veil is
the drill-ground, the work-yard where the
preparations for departure are
made.
Here hasten the humble little
creatures, running indefatigably to and
fro. When the sun shines upon them,
they become gleaming specks and form
upon the milky background of the veil a
sort of constellation, a reflex
of those remote points in the sky where the
telescope shows us endless
galaxies of stars. The immeasurably small and the
immeasurably large are
alike in appearance. It is all a matter of
distance.
But the living nebula is not composed of fixed stars; on the
contrary,
its specks are in continual movement. The young Spiders never
cease
shifting their position on the web. Many let themselves drop, hanging
by
a length of thread, which the faller's weight draws from the
spinnerets.
Then quickly they climb up again by the same thread, which they
wind
gradually into a skein and lengthen by successive falls. Others
confine
themselves to running about the web and also give me the impression
of
working at a bundle of ropes.
The thread, as a matter of fact, does
not flow from the spinneret; it is
drawn thence with a certain effort. It is
a case of extraction, not
emission. To obtain her slender cord, the Spider
has to move about and
haul, either by falling or by walking, even as the
rope-maker steps
backwards when working his hemp. The activity now displayed
on the drill-
ground is a preparation for the approaching dispersal. The
travellers
are packing up.
Soon we see a few Spiders trotting briskly
between the table and the open
window. They are running in mid-air. But on
what? If the light fall
favourably, I manage to see, at moments, behind the
tiny animal, a thread
resembling a ray of light, which appears for an
instant, gleams and
disappears. Behind, therefore, there is a mooring, only
just
perceptible, if you look very carefully; but, in front, towards
the
window, there is nothing to be seen at all.
In vain I examine
above, below, at the side; in vain I vary the direction
of the eye: I can
distinguish no support for the little creature to walk
upon. One would think
that the beastie were paddling in space. It
suggests the idea of a small
bird, tied by the leg with a thread and
making a flying rush
forwards.
But, in this case, appearances are deceptive: flight is
impossible; the
Spider must necessarily have a bridge whereby to cross the
intervening
space. This bridge, which I cannot see, I can at least
destroy. I
cleave the air with a ruler in front of the Spider making for the
window.
That is quite enough: the tiny animal at once ceases to go forward
and
falls. The invisible foot-plank is broken. My son, young Paul, who
is
helping me, is astounded at this wave of the magic wand, for not even
he,
with his fresh, young eyes, is able to see a support ahead for
the
Spiderling to move along.
In the rear, on the other hand, a thread
is visible. The difference is
easily explained. Every Spider, as she goes,
at the same time spins a
safety-cord which will guard the rope-walker against
the risk of an
always possible fall. In the rear, therefore, the thread is
of double
thickness and can be seen, whereas, in front, it is still single
and
hardly perceptible to the eye.
Obviously, this invisible
foot-bridge is not flung out by the animal: it
is carried and unrolled by a
gust of air. The Epeira, supplied with this
line, lets it float freely; and
the wind, however softly blowing, bears
it along and unwinds it. Even so is
the smoke from the bowl of a pipe
whirled up in the air.
This floating
thread has but to touch any object in the neighbourhood and
it will remain
fixed to it. The suspension-bridge is thrown; and the
Spider can set
out. The South-American Indians are said to cross the
abysses of the
Cordilleras in travelling-cradles made of twisted
creepers; the little Spider
passes through space on the invisible and the
imponderable.
But to
carry the end of the floating thread elsewhither a draught is
needed. At
this moment, the draught exists between the door of my study
and the window,
both of which are open. It is so slight that I do not
feel its; I only know
of it by the smoke from my pipe, curling softly in
that direction. Cold air
enters from without through the door; warm air
escapes from the room through
the window. This is the drought that
carries the threads with it and enables
the Spiders to embark upon their
journey.
I get rid of it by closing
both apertures and I break off any
communication by passing my ruler between
the window and the table.
Henceforth, in the motionless atmosphere, there are
no departures. The
current of air is missing, the skeins are not unwound and
migration
becomes impossible.
It is soon resumed, but in a direction
whereof I never dreamt. The hot
sun is beating on a certain part of the
floor. At this spot, which is
warmer than the rest, a column of lighter,
ascending air is generated. If
this column catch the threads, my Spiders
ought to rise to the ceiling of
the room.
The curious ascent does, in
fact, take place. Unfortunately, my troop,
which has been greatly reduced by
the number of departures through the
window, does not lend itself to
prolonged experiment. We must begin
again.
The next morning, on the
same yucca, I gather the second family, as
numerous as the
first. Yesterday's preparations are repeated. My legion
of Spiders first
weaves a divergent framework between the top of the
brushwood placed at the
emigrants' disposal and the edge of the table.
Five or six hundred wee
beasties swarm all over this work-yard.
While this little world is busily
fussing, making its arrangements for
departure, I make my own. Every
aperture in the room is closed, so as to
obtain as calm an atmosphere as
possible. A small chafing-dish is lit at
the foot of the table. My hands
cannot feel the heat of it at the level
of the web whereon my Spiders are
weaving. This is the very modest fire
which, with its column of rising air,
shall unwind the threads and carry
them on high.
Let us first enquire
the direction and strength of the current. Dandelion-
plumes, made lighter
by the removal of their seeds, serve as my guides.
Released above the
chafing-dish, on the level of the table, they float
slowly upwards and, for
the most part, reach the ceiling. The emigrants'
lines should rise in the
same way and even better.
The thing is done: with the aid of nothing that
is visible to the three
of us looking on, a Spider makes her ascent. She
ambles with her eight
legs through the air; she mounts, gently swaying. The
others, in ever-
increasing numbers, follow, sometimes by different roads,
sometimes by
the same road. Any one who did not possess the secret would
stand amazed
at this magic ascent without a ladder. In a few minutes, most
of them
are up, clinging to the ceiling.
Not all of them reach it. I
see some who, on attaining a certain height,
cease to go up and even lose
ground, although moving their legs forward
with all the nimbleness of which
they are capable. The more they
struggle upwards, the faster they come
down. This drifting, which
neutralizes the distance covered and even
converts it into a
retrogression, is easily explained.
The thread has
not reached the platform; it floats, it is fixed only at
the lower end. As
long as it is of a fair length, it is able, although
moving, to bear the
minute animal's weight. But, as the Spider climbs,
the float becomes shorter
in proportion; and the time comes when a
balance is struck between the
ascensional force of the thread and the
weight carried. Then the beastie
remains stationary, although continuing
to climb.
Presently, the
weight becomes too much for the shorter and shorter float;
and the Spider
slips down, in spite of her persistent, forward striving.
She is at last
brought back to the branch by the falling threads. Here,
the ascent is soon
renewed, either on a fresh thread, if the supply of
silk be not yet
exhausted, or on a strange thread, the work, of those who
have gone
before.
As a rule, the ceiling is reached. It is twelve feet high. The
little
Spider is able, therefore, as the first product of her
spinning-mill,
before taking any refreshment, to obtain a line fully twelve
feet in
length. And all this, the rope-maker and her rope, was contained in
the
egg, a particle of no size at all. To what a degree of fineness can
the
silky matter be wrought wherewith the young Spider is
provided! Our
manufacturers are able to turn out platinum-wire that can only
be seen
when it is made red-hot. With much simpler means, the Spiderling
draws
from her wire-mill threads so delicate that, even the brilliant light
of
the sun does not always enable us to discern them.
We must not let
all the climbers be stranded on the ceiling, an
inhospitable region where
most of them will doubtless perish, being
unable to produce a second thread
before they have had a meal. I open
the window. A current of lukewarm air,
coming from the chafing-dish,
escapes through the top. Dandelion-plumes,
taking that direction, tell
me so. The wafting threads cannot fail to be
carried by this flow of air
and to lengthen out in the open, where a light
breeze is blowing.
I take a pair of sharp scissors and, without shaking
the threads, cut a
few that are just visible at the base, where they are
thickened with an
added strand. The result of this operation is
marvellous. Hanging to
the flying-rope, which is borne on the wind outside,
the Spider passes
through the window, suddenly flies off and disappears. An
easy way of
travelling, if the conveyance possessed a rudder that allowed
the
passenger to land where he pleases! But the little things are at
the
mercy of the winds: where will they alight? Hundreds, thousands of
yards
away, perhaps. Let us wish them a prosperous journey.
The
problem of dissemination is now solved. What would happen if
matters,
instead of being brought about by my wiles, took place in the
open
fields? The answer is obvious. The young Spiders, born acrobats
and
rope-walkers, climb to the top of a branch so as to find sufficient
space
below them to unfurl their apparatus. Here, each draws from her
rope-factory
a thread which she abandons to the eddies of the air. Gently
raised by the
currents that ascend from the ground warmed by the sun,
this thread wafts
upwards, floats, undulates, makes for its point of
contact. At last, it
breaks and vanishes in the distance, carrying the
spinstress hanging to
it.
The Epeira with the three white crosses, the Spider who has supplied
us
with these first data concerning the process of dissemination, is
endowed
with a moderate maternal industry. As a receptacle for the eggs,
she
weaves a mere pill of silk. Her work is modest indeed beside the
Banded
Epeira's balloons. I looked to these to supply me with fuller
documents.
I had laid up a store by rearing some mothers during the
autumn. So that
nothing of importance might escape me, I divided my stock of
balloons,
most of which were woven before my eyes, into two sections. One
half
remained in my study, under a wire-gauze cover, with, small bunches
of
brushwood as supports; the other half were experiencing the
vicissitudes
of open-air life on the rosemaries in the
enclosure.
These preparations, which promised so well, did not provide me
with the
sight which I expected, namely, a magnificent exodus, worthy of
the
tabernacle occupied. However, a few results, not devoid of interest,
are
to be noted. Let us state them briefly.
The hatching takes place
as March approaches. When this time comes, let
us open the Banded Epeira's
nest with the scissors. We shall find that
some of the youngsters have
already left the central chamber and
scattered over the surrounding
eiderdown, while the rest of the laying
still consists of a compact mass of
orange eggs. The appearance of the
younglings is not simultaneous; it takes
place with intermissions and may
last a couple of weeks.
Nothing as
yet suggests the future, richly-striped livery. The abdomen
is white and, as
it were, floury in the front half; in the other half it
is a
blackish-brown. The rest of the body is pale-yellow, except in
front, where
the eyes form a black edging. When left alone, the little
ones remain
motionless in the soft, russet swan's-down; if disturbed,
they shuffle lazily
where they are, or even walk about in a hesitating
and unsteady fashion. One
can see that they have to ripen before
venturing outside.
Maturity is
achieved in the exquisite floss that surrounds the natal
chamber and fills
out the balloon. This is the waiting-room in which the
body hardens. All
dive into it as and when they emerge from the central
keg. They will not
leave it until four months later, when the midsummer
heats have
come.
Their number is considerable. A patient and careful census gives
me
nearly six hundred. And all this comes out of a purse no larger than
a
pea. By what miracle is there room for such a family? How do
those
thousands of legs manage to grow without straining
themselves?
The egg-bag, as we learnt in Chapter II., is a short cylinder
rounded at
the bottom. It is formed of compact white satin, an insuperable
barrier.
It opens into a round orifice wherein is bedded a lid of the
same
material, through which the feeble beasties would be incapable
of
passing. It is not a porous felt, but a fabric as tough as that of
the
sack. Then by what mechanism is the delivery effected?
Observe
that the disk of the lid doubles back into a short fold, which
edges into the
orifice of the bag. In the same way, the lid of a
saucepan fits the mouth by
means of a projecting rim, with this
difference, that the rim is not attached
to the saucepan, whereas, in the
Epeira's work, it is soldered to the bag or
nest. Well, at the time of
the hatching, this disk becomes unstuck, lifts
and allows the new-born
Spiders to pass through.
If the rim were
movable and simply inserted, if, moreover, the birth of
all the family took
place at the same time, we might think that the door
is forced open by the
living wave of inmates, who would set their backs
to it with a common
effort. We should find an approximate image in the
case of the saucepan,
whose lid is raised by the boiling of its contents.
But the fabric of the
cover is one with the fabric of the bag, the two
are closely welded; besides,
the hatching is effected in small batches,
incapable of the least
exertion. There must, therefore, be a spontaneous
bursting, or dehiscence,
independent of the assistance of the youngsters
and similar to that of the
seed-pods of plants.
When fully ripened, the dry fruit of the snap-dragon
opens three windows;
that of the pimpernel splits into two rounded halves,
something like
those of the outer case of a fob-watch; the fruit of the
carnation partly
unseals its valves and opens at the top into a star-shaped
hatch. Each
seed-casket has its own system of locks, which are made to work
smoothly
by the mere kiss of the sun.
Well, that other dry fruit, the
Banded Epeira's germ-box, likewise
possesses its bursting-gear. As long as
the eggs remain unhatched, the
door, solidly fixed in its frame, holds good;
as soon as the little ones
swarm and want to get out, it opens of
itself.
Come June and July, beloved of the Cicadae, no less beloved of
the young
Spiders who are anxious to be off. It were difficult indeed for
them to
work their way through the thick shell of the balloon. For the
second
time, a spontaneous dehiscence seems called for. Where will it
be
effected?
The idea occurs off-hand that it will take place along
the edges of the
top cover. Remember the details given in an earlier
chapter. The neck
of the balloon ends in a wide crater, which is closed by a
ceiling dug
out cup-wise. The material is as stout in this part as in any
other;
but, as the lid was the finishing touch to the work, we expect to find
an
incomplete soldering, which would allow it to be unfastened.
The
method of construction deceives us: the ceiling is immovable; at no
season
can my forceps manage to extract it, without destroying the
building from top
to bottom. The dehiscence takes place elsewhere, at
some point on the
sides. Nothing informs us, nothing suggests to us that
it will occur at one
place rather than another.
Moreover, to tell the truth, it is not a
dehiscence prepared by means of
some dainty piece of mechanism; it is a very
irregular tear. Somewhat
sharply, under the fierce heat of the sun, the
satin bursts like the rind
of an over-ripe pomegranate. Judging by the
result, we think of the
expansion of the air inside, which, heated by the
sun, causes this
rupture. The signs of pressure from within are manifest:
the tatters of
the torn fabric are turned outwards; also, a wisp of the
russet eiderdown
that fills the wallet invariably straggles through the
breach. In the
midst of the protruding floss, the Spiderlings, expelled from
their home
by the explosion, are in frantic commotion.
The balloons of
the Banded Epeira are bombs which, to free their
contents, burst under the
rays of a torrid sun. To break they need the
fiery heat-waves of the
dog-days. When kept in the moderate atmosphere
of my study, most of them do
not open and the emergence of the young does
not take place, unless I myself
I have a hand in the business; a few
others open with a round hole, a hole so
neat that it might have been
made with a punch. This aperture is the work of
the prisoners, who,
relieving one another in turns, have, with a patient
tooth, bitten
through the stuff of the jar at some point or
other.
When exposed to the full force of the sun, however, on the
rosemaries in
the enclosure, the balloons burst and shoot forth a ruddy flood
of floss
and tiny animals. That is how things occur in the free sun-bath of
the
fields. Unsheltered, among the bushes, the wallet of the Banded
Epeira,
when the July heat arrives, splits under the effort of the inner
air. The
delivery is effected by an explosion of the dwelling.
A very
small part of the family are expelled with the flow of tawny
floss; the vast
majority remain in the bag, which is ripped open, but
still bulges with
eiderdown. Now that the breach is made, any one can go
out who pleases, in
his own good time, without hurrying. Besides, a
solemn action has to be
performed before the emigration. The animal must
cast its skin; and the
moult is an event that does not fall on the same
date for all. The
evacuation of the place, therefore, lasts several
days. It is effected in
small squads, as the slough is flung aside.
Those who sally forth climb
up the neighbouring twigs and there, in the
full heat of the sun, proceed
with the work of dissemination. The method
is the same as that which we saw
in the case of the Cross Spider. The
spinnerets abandon to the breeze a
thread that floats, breaks and flies
away, carrying the rope-maker with
it. The number of starters on any one
morning is so small as to rob the
spectacle of the greater part of its
interest. The scene lacks animation
because of the absence of a crowd.
To my intense disappointment, the
Silky Epeira does not either indulge in
a tumultuous and dashing exodus. Let
me remind you of her handiwork, the
handsomest of the maternal wallets, next
to the Banded Epeira's. It is
an obtuse conoid, closed with a star-shaped
disk. It is made of a
stouter and especially a thicker material than the
Banded Epeira's
balloon, for which reason a spontaneous rupture becomes more
necessary
than ever.
This rupture is effected at the sides of the bag,
not far from the edge
of the lid. Like the ripping of the balloon, it
requires the rough aid
of the heat of July. Its mechanism also seems to work
by the expansion
of the heated air, for we again see a partial emission of
the silky floss
that fills the pouch.
The exit of the family is
performed in a single group and, this time,
before the moult, perhaps for
lack of the space necessary for the
delicate casting of the skin. The
conical bag falls far short of the
balloon in size; those packed within would
sprain their legs in
extracting them from their sheaths. The family,
therefore, emerges in a
body and settles on a sprig hard by.
This is a
temporary camping-ground, where, spinning in unison, the
youngsters soon
weave an open-work tent, the abode of a week, or
thereabouts. The moult is
effected in this lounge of intersecting
threads. The sloughed skins form a
heap at the bottom of the dwelling;
on the trapezes above, the flaylings take
exercise and gain strength and
vigour. Finally, when maturity is attained,
they set out, now these, now
those, little by little and always
cautiously. There are no audacious
flights on the thready airship; the
journey is accomplished by modest
stages.
Hanging to her thread, the
Spider lets herself drop straight down, to a
depth of nine or ten inches. A
breath of air sets her swinging like a
pendulum, sometimes drives her against
a neighbouring branch. This is a
step towards the dispersal. At the point
reached, there is a fresh fall,
followed by a fresh pendulous swing that
lands her a little farther
afield. Thus, in short tacks, for the thread is
never very long, does
the Spiderling go about, seeing the country, until she
comes to a place
that suits her. Should the wind blow at all hard, the
voyage is cut
short: the cable of the pendulum breaks and the beastie is
carried for some distance on its cord. |
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