Insects that Build
Submarines
By A. Hyatt Verrill
Everyland magazine August 1916. Column, ‘Everyland
Nature Club’; digitized by Doug Frizzle, Dec. 2011.
THAT sounds funny, doesn't
it? Perhaps you think it's a joke, for we're so accustomed to think of
submarines as wonderful inventions of our own that it's hard to believe such
tiny things as insects made and used submarines ages before man first thought
of building a boat of any kind.
But, queer as it seems,
insects do build and use submarines and moreover they
are very common, and any reader of Everyland
who lives near a pond or stream—in temperate America, at least—can find these interesting little chaps and can watch them as they
move about beneath the water. Even
better, you can catch them, carry them home in jars or pails of water, and keep them in your own home in an aquarium where they'll be just as happy and interesting as ever.
But you musn't expect to find
these insects rushing about in tight
steel submarines and destroying other
insects by torpedoes or mines. No, indeed! The submarines built by the insects are used for very different purposes and
are made very differently from those which men use for the
purpose of destroying ships and killing their
fellow men. The insects use their submarines for their homes and to protect themselves
from enemies; and comfort and convenience, as well as safety, are far more
important to the insects than are
speed and destructiveness. But the
insects' submarines are very cleverly and neatly built and are upholstered with
the finest of silk. And the insect owners don't need periscopes nor
machinery in their tiny submarines, for they are moved about by means of their owners' strong feet and never have to come up
to the surface of the water for air or to have a look about. If they did that, some hungry bird might see them and gobble them
down, submarine, insect and all, and, moreover, it isn't necessary, for these queer insects can breathe
and can see at the bottom of the water just as well as when they're at the
top; which is something we humans cannot do with all our brains and science and
inventions.
But now you must be curious
to know what these funny insects are
like, and what they are, and how they live, and so we'll take a stroll to some shady
pool or sparkling brook and see them
for ourselves.
Place your face close to the surface of the
water and look carefully at the sandy
bottom beneath. At first you may not see anything but a few pebbles, some little
bundles of sticks and some funny little cylinders of sand. But don't be
discouraged, and in a moment you will be surprised to see some of these objects move about upon the
bottom. Take them out and they are apparently dead and inanimate and, unless
you know the secret, you would never
guess that these ordinary looking
things are insects' submarines.
But if you should break one
open you would find it a hollow tube lined with soft and shining silk and with
a pale, whitish, caterpillar wriggling about inside and very excited and
indignant at having his snug home destroyed.
But it is much easier and
kinder to watch the funny insects in
a glass jar or aquarium, and in this way you may learn just how the caterpillar builds his submarine, how he makes
it travel here and there, and, best
of all, what happens when his short life is over.
If the
little fellow thinks he's safe he'll cautiously move his head out from his
silk-lined submarine home; then
he'll look about and, if nothing frightens him, he'll crawl out until his
little legs can grasp the object on
which he rests, and then he'll walk
about pulling his funny submarine with him.
And if you have sharp eyes
and are interested in nature, and bugs, and live things, you'll notice that there are many different forms of these submarines. Some are little cylinders made of
tiny sticks, or bits of grass or straws placed lengthwise side by side; others are like little log huts of the tiniest sticks or straws fastened together criss-cross; others
are made of dainty little shells stuck together,
and others are made of bits of moss
and leaves, but most are made of tiny pebbles or grains of sand. But even these are of many different shapes. Some are like
straight tubes, others are coiled
like snail-shells, others are like
little balls, and some are pointed at one end and look like the tusks of fairy elephants.
Although you cannot see any
difference in the various
caterpillars which make these
submarines and live within them, yet
each form of home contains a different kind of owner; and while they are all known as caddis-worms, there are many different species. Each specie always
builds a certain kind of submarine house, each has distinct habits, and each is
the larva of a pretty, winged insect
known as a caddis-fly.
Some of the submarine caterpillars are carpenters, some are
masons, and, in addition, many of them
are expert fishermen and spread silken nets between the
stones to capture their prey. Their
tiny nets are funnel-shaped with the
larger end pointed up the stream,
but another kind of caddis-worm
weaves little oval cups which are fastened to rocks on the
edges of falls and cataracts. Both kinds of nets are kept open by the current and any minute creatures which are so
unfortunate as to enter them are
devoured by the hungry little
builders of the submarines.
But the
nets catch all sorts of dirt and rubbish as well as live things, and you often
may see rocks completely covered with dirt which has lodged in the insect fishermen's nets and has hidden them completely out of sight.
By and by, when the caddis-worm has grown to full size, he feels
dull and sleepy and drawing himself inside his submarine he closes his odd home
with a silken door, leaving a tiny window for the
water to enter, and then goes sound
asleep. As he slumbers he wriggles out of his skin and changes to a shiny brown
pupa or chrysalis. Then at last his sleep is over and the
pupa bursts open and a queer little insect, very different from the caterpillar, gnaws through the silk door. It is a funny, damp creature with two
long legs, and, using these legs for
oars, the little fellow swims up to the surface of the
water toward the nearest rock or
stick.
Somehow he seems to have
forgotten all about submarines and fish-nets, and, anxious to get to the open air, crawls up out of the water. Then a very wonderful thing happens, for
two little pads upon his back swell up and change as if by magic into four
delicate, hairy, brown wings. All his life this insect has lived at the bottom of the
pond or brook; all his life he has crawled about, dragging his submarine house,
or has slept inside a brown pupa. Never before has he been out of the water, never before has he possessed wings, and
no doubt you think he'll have trouble learning to use them.
But in that you'll be greatly mistaken, for no sooner do the
little pads unfold than the
caddis-fly spreads his new wings and flies away as gaily as though he'd used them all his life.
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