The Caldwell tribune. [volume] (Caldwell, Idaho Territory [Idaho]) 1883-1928, 1894-02-03
PROTECTING COLOR IN ANIMALS.
Discussion as to What 1t Is That Gives
Many Creatures Their COlors.

A Discussion as to What 1t Is That Gives
Many Creatures Their Colors.
Where lichen covered tree stems are COM
mon, we find lichen colored caterpillars,
moths and other insects. A pretty moth
(Cleora glabraria), not uncommon III the
New Forest, is white busted with tlack,
and it's larva, which feeds upon ichens, is
of the same color. Some years ago, while
collecting insects in that locality, found
in the same tufts of lichen small black
and white spider just as closely resembling
the ichens.
1t is supposed that these various color
resemblances have been brought about by
the need for concealment. A caterpillar
frequenting lichens, or a bird living among
leaves, would b. greatly advantaged by a
color resemblance to their several sur
roundings; hence variations in the required
direction have escaped destruction, and
there has been through long ages grad
ual perfecting of the rese1lblances. This
is the most generally received explanations;
it accounts also for the coloration of ami
mails like the spider, to which l have re-
ferred, which do not so much need protec-
ton from their enemies as disguise with
the help of which they can steal upon their
prey.
We must, however, guard against taking
generalities for granted without a careful
examination of the several cases. Many
years ago Messrs. Kirby and Spence called
attention to the resemblance between
ichen feeding insects and their food:
'Many of the notified moths which take
their station of diurnal repose on the north
side of the trunks of trees are with diff
Guilty distinguished from the gray and
green ichens that cover them. OF this
kind are Miselia apriliana and Acronycta
psi. The caterpillar of Bryophila algae,
when it feeds on the yellow Lichen juni-
perinus, is always yellow; but when upon
the gray Lichen saxatilis it's hue becomes
gray. This change is probably produced
by the color of its food"
The last sentence contains most note
worthy suggestion, which may help us in
explaining many similar cases of cOlora-
ton in much simpler way than by natu-
raj selection or natural elimination. 1t is
well known that the pigments which are
often the cause of the colors in animals, and
always, except in the case of white, OF
plants, are extremely resistent to chem
ical action. Some of these pigments will
pass unscathed through the strongest acids
and the most powerful alkalis 1t is quite
conceivable, then, that they will be equally
unaffected by the chemical action of an ami
mails digestive juices.
There is, however, no need at all for
theory upon this point; it has been shown
to be the case in several instances. DR..
Eisig found in The Mediterranean species
of worm living in the interior of sponge.
The sponge was a brilliant yellow, the
color being due to particles of a peculiar
pigment deposited in its tissues. The
worm was also yellow, and it might be
supposed that this harmony had been
brought about by the necessity for conceal
ment. An inquisitive fish poking it's nose
into the interior of the sponge, in search OF
the various small creatures which COZ
stantly take up their lodgings in such
spot, would pass over the ''protectively
colored" worm, and select one that was
obvious on account of its different colors.
It was found, however, that the color of
the worm was merely due to. particles of
the coloring substance of the host, which
had passed out of the intestine of the worm
into its skiD.-BlackWOOd's MAGAZINE,