The Denison review. [volume] (Denison, Iowa) 1867-current, 1906-07-12
INSECT ENGINEERING
FEATs OF THE CARPENTER BEE AND
THE TuMBLEBuG.

The Sexton Beetle Is an Expert
Gravcdigger Wonderful Skill OF
the Spider and the Great Strain
Tint His Elastic Web Will Bear,
Long before man had thought of the
saw the saw fly had used the same
tool, made after the same fashion and
used in the same way, for the purpose
of making Sits in the branches of trees
so that she might have Il secure place
to deposit her eggs. The carpenter bee,
! with only the tools which nature has
given her, cuts a round hole the full
diameter of her body, through thick
boards and so makes a tunnel by which
she can have safe retreat in which to
rear her young The tumblebug, with
out derrick or machinery, rolls over
large masses of dirt many times her
| own weight, and the sexton beetle will
in few hours bury beneath the ground
the carcass of a comparatively large
animal. All these feats require de
| gree OF instinct which in reasoning
creature would be called engineering
skill, but none of them is as wonder
full as the feats performed by the spi-
der. This extraordinary little animal
has the faculty of propeling her
threads directly against the wind, and
Z. by means of her slender cords she can
haul up and suspend bodies which are
many times her own weight.
Some years ago paragraph went the
rounds of the papers in which it was
said that a spider had suspended an
unfortunate mouse, raising it from the
ground and leaving it to perish misera-
bly, between heaven and earth. Would
be philosophers made great fun of the
statement and ridiculed it unmerciful-
| ~. know not how true it was, but
know that it might have been true.
Some years ago in the village of Ha-
vana in the state of New York spider
entangled milk snake in her threads
and actually raised it some distance
from the ground, and this, too, in spite
of the struggles of the reptile. which
was alive.
BY what process of engineering did
this comparatively small and feeble in
sect succeed in overcoming and lifting
up by mechanical means the mouse or
the snake? The solution is easy
enough if we only give the question
little thought
The spider is furnished with one of
the most efficient mechanical imple-
ments known to engineers-viz,
strong elastic thread. That the thread
is strong is well known Indeed, there
are few substances that will support
greater strain than the silk of the silk
worm or the spider, careful expert
ment having shown that for equal sizes
the strength of these tibers exceeds that
of common iron. But Notwithstanding
Its strength the SPIDERS thread would
be useless as a mechanical power if it
were not for it's elasticity. The spider
has no blocks or pulleys, and therefore
1T cannot cause the thread to divide up
and run in lifferent directions, but the
elasticity of the thread more than
makes up for this and renders possible
the lifting of an animal much heavier.
than mouse or snake. This may
require little explanation.
Let us suppose that child can lift
a six pound weight one foot high and
Wv tAlS wv elty llulcS Il Hlllute. i uT-
nish him with $50 rubber bands, each
capable of pulling six pounds through
one foot when stretched. Let these
bands be attached to wooden plat
form on which stands pair of horses
weighing 2,100 pounds, or rather more
than a ton. If now the child will go to
work and stretch these rubber bands
singly, hooking each one up as it is
stretched, in less than twenty minutes
he will have raised the pair of horses
one foot
1 We thus see that the elasticity of the
rubber bands enables the child to di-
vide the weight Of horses into $50
pieces of six pounds each, and, at the
rate of little less than one every
three seconds, he lifts all these sepa-
rate pieces one foot, so that the child
easily lifts this enormous weight
Each SPIDERS thread acts like one of
the elastic rubber bands. Let us sup
pose that the mouse or snake weighed
half an ounce and that each thread is
capable of supporting grain and a
half. The spider would have to connect
the mouse with the point from which
it was to be suspended with $50
threads, and if the little quadruped
was once swung off his fee. he would
be powerless. BY pulling successfully
) on each thread, and shortcn.ag it lit
tie, the mouse or snake might be raised
to any height within the capacity Of
the building or structure in which the
work was done. So that II those who
have ridiculed the sto:y we may justly
say, "There are more things in heaven
and earth than are dreamed of in your.
philosophy"
i, What object the spider could have.
had in his work am unable to see. 1t
may have been a dread of the harm
which the mouse or snake might work
or it may have been the hope that the
decaying carcass would attract flies,
: which would furnish food for the engi-
neer. can vouch for the truth of the.
snake story, however, and the object