Get a taste of what awaits you in print from this compelling excerpt.

Armor shields, seductive smells, artful camouflage—such are the physical and behavioral tools wielded by carnivorous caterpillars. In Hawaii they may hunt disguised as a bit of bark. In Denmark some live underground, pampered by ants. One Australian species invades green tree ant nests, devouring the brood. This craving for prey is highly unusual: Of the roughly 160,000 known butterfly and moth species, less than one percent eat meat, usually soft-bodied insects and spiders. Some begin life eating a specific type of plant, then switch to a particular species of insect. Such complex life cycles make these carnivores extremely hard to find—and vulnerable to extinction.

* * * * * *

All of Hawaii's 20 known species of Eupithecia blend imperceptibly into their surroundings. Some look like flecks of leaf litter, lichen, or moss. Though hundreds of species of Eupithecia exist all over the world, most feed exclusively on flowers and fruits. Hawaii is the only place where they live as carnivores—an intriguing twist of evolution.

* * * * * *

Rarely observed, this brazen feeding behavior originates with smell. On the Danish island of Læsø the Maculinea alcon butterfly begins life as a tiny white egg on a marsh gentian. After hatching, the caterpillar feeds on the flower for about two weeks before dropping to the ground. A waxy coat of hydrocarbons on its body smells nearly identical to Myrmica ant larvae. Fooled by the smell, passing ants will mistake the caterpillar for one of their own and carry it into their nest. There they willingly feed it regurgitated liquids mouth to mouth, a diet it supplements by eating the ants' brood. Once the caterpillar becomes a butterfly it must quickly flee the nest, spread its wings and begin the cycle anew.

Get the whole story in the pages of National Geographic magazine.

Its prey in a death grip, a carnivorous caterpillar devours a defenseless fly. RealPlayer  WinMedia RealPlayer Broadband

Listen to the amplified drumming and grunts of Maculinea alcon caterpillars inside a nest of chittering Myrmica ants. Viewing this interactive multimedia requires Flash.

Acid-squirting ants—who could imagine such a thing? Yet they exist. In Australia these ants are a vital counterpart to a species of carnivorous caterpillars called Arhopala wildei. These caterpillars prey on the broods of rattle-ants (Polyrachis queenslandica), which are named for a particular defensive behavior. Besides actually squirting acid from their gasters, or abdomens, these ants also tap their gasters on a leaf or the nest surface when threatened. When a large number of ants in a nest tap, they make a reasonably loud rattling noise—hence the name. These vibrations and sounds travel well in trees and serve to warn the colony of danger. If there is a disturbance to the nest, rattle-ants pick up bunches of their brood and move them to safety. Interestingly, carnivorous A. wildei caterpillars, in later stages, may have evolved to imitate this behavior, mimicking the tapping sounds of the ants. Although this behavior has not been studied in detail, it has been hypothesized that being able to make these warning sounds could increase the overall level of protection to the ant nest, thereby providing better protection for the A. wildei larvae that live with the ants. When the ants move their brood, the caterpillar larvae are carried to safer corners of the nest as well.

—Mimi McLearn