Some butterflies defend against predators in
incorporating toxins when they are caterpillars and eat plants containing these
substances. The monarch butterfly is an example for this. Its caterpillars feed
on milkweed plants which aren’t poisonous for the monarch but for other
animals. The monarch’s bright colors warn predators better not to eat this
butterfly only causing sickness. Having eaten such a butterfly once a bird will
always remember to keep away from it.
Other species of butterflies which are not poisonous try to profit from the
protective coloration, too. The viceroy butterfly mimics the monarch, for
example. Over the years and generations the coloring developed by natural
selection. Considering them poisonous, predators didn’t eat the ones looking
like monarchs. This is called Batesian mimicry.
Original
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"Copy"
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The behavior of the "model" is also imitated and sometimes the
mimicking butterflies fly with them in one group.
Some species can mimic several different "models". The descendants
of one female can have up to three different appearances.
The males of another species must dispense with mimicry so that the females
don’t mistake them for the ones of the copied species.
Not only poisonous and inedible butterflies but also wasps, hornets, bumblebees and
poisonous beetles are mimicked. The sphinx moth caterpillar even imitates a
venomous snake when it feels menaced.
Another kind of mimicry is called "Mullerian mimicry". The monarch
butterfly and the milkweed bug for example have the same bright coloring and
store the same toxin. This might be useful because the predators of the area
must only remember one kind of coloration to keep away from. One experience
saves the lives of two species.