Bright colors help many animals find others of their species
and communicate with them. They may also help hide animals
in their habitats. Yet, bright colors can also be warning colors.
Many animals that are poisonous, bad tasting, or both are clad in
warning colors. The colors say to predators, “Don’t even think of
attacking me. You’ll be sorry.”
|A cinnabar caterpillar is foul tasting and poisonous, and its
black warning colors are meant to keep
A predator that licks, mouths, or bites an animal with warning
colors often drops or spits out its prey. The prey may taste
bad, or irritate the predator’s mouth. If the prey’s poison is strong,
it may also make the predator feel sick and throw up. After one or
more experiences like this, the predator learns that it is a bad idea
to attack this sort of prey. It is unlikely to go after another animal
that looks like this disastrous meal.
Disgusting or sickening a predator in this way may be a better
strategy for a prey animal than killing the predator. It is useful
to have “educated” predators in the neighborhood—predators
that will steer clear of the prey.
The most widely used warning colors are red, orange, yellow,
black, or a combination of these. The iron-cross blister beetle,
for example, has a black body, red head, and yellow wing covers
marked with black bands. Like other blister beetles, it oozes irritating
oil when seized by a predator. The oil causes blisters to
form on the predator’s skin.
Another noxious animal, the koppie foam grasshopper of
South Africa, is black with red stripes. If it is attacked, a smelly, poisonous foam bubbles from its body. The foam not only makes
the grasshopper taste bad, but it also is strong enough to kill a
dog. Likewise, the lubber grasshopper of the southeastern United
States is clad in warning colors of black and yellow. It also bubbles
an irritating foam that is toxic enough to kill a bird. Opossums
that swallow a lubber quickly throw it up.
Ladybugs with bright red shells and black dots are also wearing
warning colors. The bright pattern signals that the ladybug
may sicken or kill a small animal that eats it. A bird, lizard, or insect
that ignores the warning and grabs the ladybug gets a second
warning in the form of a smelly, bad-tasting yellow liquid that oozes from the insect’s joints. This oozing is called reflex bleeding
in addition to smelling and tasting awful, the fluid clogs up
an insect predator’s jaws. The ladybug’s orange-and-black young
also use reflex bleeding as a defense.
Moths, butterflies, and caterpillars that are poor-tasting or
poisonous have warning colors as well. The white, black, and yellow
caterpillar of the monarch butterfly, for example, is poisonous.
The orange-and-black-striped caterpillars of the cinnabar
moth are poisonous, too.
European magpie moths are boldly patterned at every stage
of life. in their youth, their white, black, and red caterpillars ooze
foul-tasting fluid that causes predators to spit them out. The caterpillars
form cocoons that are glossy black and ringed with yellow
stripes. The adult moths that hatch have white, black, and