With over 1 million described species of insects in the world, and perhaps 9 or 10 more million kinds still to put names on, it stands to reason that insects fit just about every environmental niche possible, and have a bewildering variety of life styles and appearances. Since most of the species on Earth today have been around for millions of years, it is obvious that each of them has found some mechanism that allows them to survive.
Some of the survival techniques employed include colors or shapes that camouflage the insect in its environment, looking for all the world like a dead leaf or the bark of a tree. It may be walking sticks that look like twigs, and the hope of this technique is that the bug simply cannot be seen by predators who otherwise would dine on it.
Other insects, however, show the opposite. They exhibit colors that make them obvious to all who glance their way. Their reds, yellows, pink, or orange colors make them stand out against the backdrop of their environment, and you might wonder why it is they haven't long ago been a meal for some hungry bird or lizard. In many cases, as it turns out, these bright colors are "warning" colors, and they advertise to potential predators that THIS particular bug should not be messed with, for it can fight back.
Stink
bugs, such as the Harlequin Bug, have foul smelling and tasting body fluids, and
their bright orange and black bodies warn predators away. The striped Monarch
Butterfly larva is telling predators that its body is filled with toxic
alkaloids, gained from feeding on the milkweed plants that contain these
chemicals. Wasps and bees, with their bright yellow and orange colors, advertise
their ability to sting any animal foolish enough to try to swallow them.
One group of insects that we might never think of as harmful, though, is caterpillars. When we think of butterflies and moths we think of beautiful flying insects, whose larvae are fuzzy or colorful, but certainly not dangerous. However, this group of insects includes a great many that are either toxic, distasteful, or very well known for their ability to sting. Unlike the scorpions or the wasps, the sting does not come from a "stinger" at the end of the body, but instead it comes from the many hairs located along the body of the caterpillar. These spiny hairs are called "urticating" hairs, and in many cases they are attached to small poison glands in the skin of the caterpillar.
In
some cases, should you contact the caterpillar with your skin, the effect would
just be an irritation, somewhat like touching the plant stinging nettle.
However, with a few families of the caterpillars, and with sensitive people, the
effect can be dramatic. Some of the families of butterflies and moths that have
caterpillars with urticating hairs are:
