Spiders form good subjects for a rainy-day study, and two hours spent in a
neglected garret watching these clever little beings will often arouse
such interest that we shall be glad to devote many days of sunshine to
observing those species which hunt and build, and live their lives in the
open fields. There is no insect in the world with more than six legs, and
as a spider has eight he is therefore thrown out of the company of
butterflies, beetles, and wasps and finds himself in a strange assemblage.
Even to his nearest relatives he bears little resemblance, for when we
realise that scorpions and horseshoe crabs must call him cousin, we
perceive that his is indeed an aberrant bough on the tree of creation.
Leaving behind the old-fashioned horseshoe crabs to feel their way slowly
over the bottom of the sea, the spiders have won for themselves on land a
place high above the mites, ticks, and daddy-long-legs, and in their high
development and intricate powers of resource they yield not even to the
ants and bees.
Nature has provided spiders with an organ filled always with liquid which,
on being exposed to the air, hardens, and can be drawn out into the
slender threads we know as cobweb. The silkworm encases its body with a
mile or more of gleaming silk, but there its usefulness is ended as far as
the silkworm is concerned. But spiders have found a hundred uses for their
cordage, some of which are startlingly similar to human inventions.
Those spiders which burrow in the earth hang their tunnels with silken
tapestries impervious to wet, which at the same time act as lining to the
tube. Then the entrance may be a trap-door of soil and silk, hinged with
strong silken threads; or in the turret spiders which are found in our
fields there is reared a tiny tower of leaves or twigs bound together with
silk. Who of us has not teased the inmate by pushing a bent straw into his
stronghold and awaiting his furious onslaught upon the innocent stalk!
A list of all the uses of cobwebs would take more space than we can spare;
but of these the most familiar is the snare set for unwary flies,--the
wonderfully ingenious webs which sparkle with dew among the grasses or
stretch from bush to bush. The framework is of strong webbing and upon
this is closely woven the sticky spiral which is so elastic, so ethereal,
and yet strong enough to entangle a good-sized insect. How knowing seems
the little worker, as when, the web and his den of concealment being
completed, he spins a strong cable from the centre of the web to the
entrance of his watch-tower. Then, when a trembling of his aerial spans
warns him of a capture, how eagerly he seizes his master cable and jerks
away on it, thus vibrating the whole structure and making more certain the
confusion of his victim.
What is more interesting than to see a great yellow garden-spider hanging
head downward in the centre of his web, when we approach too closely,
instead of deserting his snare, set it vibrating back and forth so rapidly
that he becomes a mere blur; a more certain method of escaping the
onslaught of a bird than if he ran to the shelter of a leaf.
Those spiders which leap upon their prey instead of setting snares for it
have still a use for their threads of life, throwing out a cable as they
leap, to break their fall if they miss their foothold. What a strange use
of the cobweb is that of the little flying spiders! Up they run to the top
of a post, elevate their abdomens and run out several threads which
lengthen and lengthen until the breeze catches them and away go the
wingless aeronauts for yards or for miles as fortune and wind and weather
may dictate! We wonder if they can cut loose or pull in their balloon
cables at will.
Many species of spiders spin a case for holding their eggs, and some carry
this about with them until the young are hatched.
A most fascinating tale would unfold could we discover all the uses of
cobweb when the spiders themselves are through with it. Certain it is that
our ruby-throated hummingbird robs many webs to fasten together the plant
down, wood pulp, and lichens which compose her dainty nest.
Search the pond and you will find another member of the spider family
swimming about at ease beneath the surface, thoroughly aquatic in habits,
but breathing a bubble of air which he carries about with him. When his
supply is low he swims to a submarine castle of silk, so air-tight that he
can keep it filled with a large bubble of air, upon which he draws from
time to time.
And so we might go on enumerating almost endless uses for the web which is
Nature's gift to these little waifs, who ages ago left the sea and have
won a place for themselves in the sunshine among the butterflies and
flowers.
* * * * *
In the balsam-perfumed shade of our northern forests we may sometimes find
growing in abundance the tiny white dwarf cornel, or bunch-berry, as its
later cluster of scarlet fruit makes the more appropriate name. These
miniature dogwood blossoms (or imitation blossoms, as the white divisions
are not real petals) are very conspicuous against the dark moss, and many
insects seem to seek them out and to find it worth while to visit them. If
we look very carefully we may find that this discovery is not original
with us, for a little creature has long ago found out the fondness of bees
and other insects for these flowers and has put his knowledge to good
use.
One day I saw what I thought was a swelling on one part of the flower, but
a closer look showed it was a living spider. Here was protective colouring
carried to a wonderful degree. The body of the spider was white and
glistening, like the texture of the white flower on which he rested. On
his abdomen were two pink, oblong spots of the same tint and shape as the
pinkened tips of the false petals. Only by an accident could he be
discovered by a bird, and when I focussed my camera, I feared that the
total lack of contrast would make the little creature all but invisible.
Confident with the instinct handed down through many generations, the
spider trusted implicitly to his colour for safety and never moved, though
I placed the lens so close that it threw a life-sized image on the
ground-glass. When all was ready, and before I had pressed the bulb, the
thought came to me whether this wonderful resemblance should be attributed
to the need of escaping from insectivorous birds, or to the increased
facility with which the spider would be able to catch its prey. At the
very instant of making the exposure, before I could will the stopping of
the movement of my fingers, if I had so wished, my question was answered.
A small, iridescent, green bee flew down, like a spark of living light,
upon the flower, and, quick as thought, was caught in the jaws of the
spider. Six of his eight legs were not brought into use, but were held far
back out of the way.
Here, on my lens, I had a little tragedy of the forest preserved for all
time.
There was no bud, no bloom upon the bowers;
The spiders wove their thin shrouds night by night;
The thistledown, the only ghost of flowers,
Sailed slowly by--passed noiseless out of sight.
Thomas Buchanan Read.
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