JANUARY
2002

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

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Great Pretenders of the Insect World


During the 1950s, The Platters had a hit song called "The Great Pretender." The Platters' song was about a human who pretended "that I'm doing well." While humans are good at pretending, insects are among the many animals that are truly the greatest of pretenders.

In the insect world, pretending often is a matter of life or death. To many insects, pretending to be something they are not is a way to avoid becoming a meal for some insect eater.

Some insects pretend to be dangerous, for instance, a fly that looks, behaves and even sounds like a bee. Most creatures, including humans, have learned that bees and wasps can sting. Consequently, encounters with bees and wasps are avoided when possible. Bee pretenders are shunned by other animals as surely as if they were bees.

Other insect pretenders just look like something that insect eaters wouldn't consider a meal. Sticks and leaves are such things. Plant parts are the food for many animals, including nearly half of all insect species on the Earth. But creatures that are predators turn up their noses or antennae when it comes to a vegetarian diet. So looking like a plant part is a good way to avoid encounters with carnivores.

Several groups of insects pretend to be plant parts. Katydids, for instance, have a look that resembles leaves. So when katydids feed in trees, as they do, they blend in nicely. Some grasshoppers use a similar approach to pretending. But many grasshoppers feed on grass plants, so their look is more like grass leaves.

Some treehoppers have shapes that make the insect resemble a thorn. So when these insects are resting, their presence turns a smooth branch into one with thorns. And, as a result, any insect predator moves on in search of its next meal.

Probably the greatest of the insect pretenders are the stick insects. This group of insects gets their common name because all of them resemble sticks or leaves. In temperate regions, most of us are familiar with the walking sticks. Walking sticks are wingless insects that feed in trees. Their long, narrow body shape and texture of the exoskeleton make them look like small sticks.

The behavior of the stick insects further enhances their great pretense. When at rest, they remain motionless. The walking sticks also extend their antennae and front legs forward to improve the illusion. The walking sticks that live in temperate regions all lack wings, which makes them look even more like sticks.

In tropical regions, the stick insects exhibit more diversity than they do in North America. The greatest diversity is reached in the Oriental tropics where some stick insects look like walking leaves. Others are quite brightly colored so that they resemble flowers. The walking sticks of the tropics are also larger than those encountered in North America. In fact, some are so much thicker-bodied that they probably should be called walking limbs!

Whether the stick insects look like leaves, twigs, limbs or flowers, they are the great pretenders of the insect world. And for good reason! For these insects, pretending to be a vegetable is a good way to avoid the attention of a meat-eating carnivore!

 

 

Writer: Tom Turpin
Editor: Olivia Maddox