OCTOBER
1997

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

10-23-97

Some Insects Have Year-Round Halloween Costumes

EDITOR'S NOTE: This column has been recycled from October 1992. It is particularly timely.

Halloween is a time when many humans don costumes and masks. It's in the spirit of the season to pretend to be some ghoulish fiend.

For most of us, since the time we were knee high to a grasshopper, pretending was a common pastime. Most grownups on occasion still like to pretend to be someone or something they're not. It's fun. Some folks even make a living at it - they're called actors!

Many insects are also actors. They frequently look and act like something they are not. For insects, the charade is not just an opportunity to have fun. The success of their deceit generally is a matter of life or death.

For many animals, insects are not just another of nature's pretty faces, but a tasty meal waiting to be eaten. To an insect, becoming a meal for a predator is high on the list of things to avoid. Insects frequently avoid this onerous fate by looking like something they are not.

Some insects appear to be dangerous. They create the illusion of being a stinging insect. Many flies have markings that make them look like bees. Some of these flies enhance the illusion by buzzing about in a bee-like fashion. There are even some beetles that behave as if they can sting like a bee. Other insects resemble wasps which, like bees, can inflict an undesirable sting on a potential predator.

A butterfly in the Orient actually looks as if it has two heads. One head is but a design on the back part of its wings. The potential predator that strikes at the fake head finds itself with a mouth or beak full of wing scales while the butterfly, with real head intact, is flying for a safe spot. Other insects have nonessential protrusions on the front of their heads. These sometimes grotesque adornments are a little like fancy chrome work on a car. Even if the chrome gets knocked off, the car will keep going.

Some butterflies and moths have spots on their wings that resemble eyes. These markings, appropriately called eyespots, make the insect appear to be an owl or snake - creatures that most insect predators would just as soon avoid. So when they notice the eyes, predators do a disappearing act. And that is good for the insect impostor.

Some insects look like inanimate objects. Walking sticks are aptly named; they look like sticks. Some caterpillars also resemble sticks or twigs. Most katydids resemble leaves. Some even carry the illusion so far that they appear to be a leaf damaged by disease or even one eaten by insects. There is a butterfly known as the “Dead Leaf Butterfly” because it looks like - you guessed it - a dead leaf.

Many treehoppers have bodies with protrusions that make the insect look like a thorn. These insects even sit on a twig in such a fashion that the “insect thorns” are all headed in the correct direction.

The all-time champion in the insect costume contest is a moth. This small moth is known as the bird dropping moth because, when at rest, it looks like a bird dropping. It's a disguise that birds seem not to notice, or at least ignore. While this insect might not win an award in the most-glamorous costume category, you've got to admit that in this bird-eat-bug world, it has a functional outfit!

 

Writer: Tom Turpin
Editor: Andrea McCann