Milford chronicle., 1903-01-30
MIMlcRY OF INSECTS.
Reaehing Chickens Not to Try to Eat
Bad Tasting CaterpiIInrs.

AEmGNAMR GmAGAAGMh NOA ANE ~ A4--N
Bad Tasting Caterpillnrs.
Professor C. Lloyd Morgan, the British
Eoologist, has recently published an ac-
count Of an interesting experiment which
helps to explain problem which has long
puzzled students of what is known as
mimicry among the lower animals.
The best known example Of mimicry is
the imitation by the South American
group of butterflies named heliconinR
By a certain species Of another group
called pierinR. The former are brightly
coIored and very slow of flight and would
naturally fall easy prey to the vast num-
Der of insectivOrous birds which inhabit
tropical countries were it not that these
butterflies have a strong, pungent Odor
which no bird would care to sample twice.
The result is that they multiply and
thrive, protected by their disagreeable
taste.
Now, the pierin@ are normally white,
OF a totally different appearance from the
heIicOnin@, and very tempting mOrsels
to birds. But there is one species Of
pierine which has abandoned the family
garb and adopted instead the colOrs and
markings Of the particular species Of
heIiconine which live in its vicinity. So
close is the resemblance that not only
birds, but experienced entomOiOgists, are
unable to distinguish between the two.
except after a close examination. The
two are totally unlike in structure. 1t is
only appearances which have changed.
Manifestly it is a great advantage to this
particular species of pierine to initiate
the markings and colors Of a butterfly so
well protected against attack as the bad
smelling heliconinR.
Such cases of mimicry as these are
easily explained. Whenever by ary
chance one Of the white, good tasting but
teriiies came to any degree resemble the
disagreeabe kind it would stand so much
better chance OF escaping destruction and
living to perpetuate its Kind. And those
white butterflies which most closely re-
sembled the colored kind would gradually
increase until in the course of evolution
the two species would have substantially
the same appearance. Such at least very
roughly is the theory now generally ac-
cepted by biologists.
There have been found, however. cases
OF mimicry by species Of butterflies which
were Just as distasteful to birds as the
kind they mimicked. Here the explana-
4ion was not so easy. Apparently one
The best hypothesis is that of Fritz Null
Ter, who argued that the advantage gain
ed when two species Of insects equally
distasteful to their enemies initiate each
other is that the young Of the enemies do
not have the experiment with more than
one species to avoid both. A young bird
having tasted a caterpillar Of one obnox-
ious class would not need to learn to let
alone a caterpillar Of the other class, pro-
yiding both looked alike to him.
It was along this line that Professor
Morgan made his experiment. He took
strips Of orange and black paper ana
pasted them beneath glass slips on which
was placed meal moistened with quinine.
ON other plain slips meal moistened with
water was placed. Some chicks were
then allowed to test both kinds. They
we're not long in learning to refuse the
bitter meal. Then they were offered some
cinnabar caterpillars, a species they had
never seen, but which has black and or
ange bands very similar to the glass slips
with the quinine favored meal. With
two exceptions the chickens refused the
caterpillars. Other birds have to learn
bv experience that these caterpillars make
DarticularIy unpleasant mouthfuls.