MARCH
1992

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

03-26-92

Small is Beautiful to Bugs

In nature bigger isn't always better, especially when it comes to insects. Even though they are small and some can't be seen without a magnifying glass, insects are one of the most successful creatures on earth.

Smallness has its advantages. For instance, insects can hide in cracks and crevices too small for most animals. Many insects escape death simply because they are overlooked due to their size. Gardeners, notorious for their desire to smash insect pests, frequently don't even know insects are around until damage begins to appear.

Another advantage to being small is that the smaller you are the less food you require. Many insects lie their lives on food wasted by larger animals. When it comes to food and insects, a little dab will do 'em.

A little wasp, which is a parasite of eggs of other insects, is only about 1/3 mm long. On the other hand, one of the largest insects is the Goliath Beetle. This mammoth among insects weighs about 1.5 ounces. A weight that makes it a little heavier than hummingbirds and shrews, the smallest birds and mammals.

Their small bodies also make it possible for insects to do some marvelous things. For instance some grasshoppers have been observed to jump nearly 10 times their height and 20 times their length. If humans could do as well, just think what the world records for the high jump and long jump might be! Some beetles can drag 120 times their body weight. An average human by competition would be able to drag about 9 tons.

Although it's an advantage for insects to be small, the way they're built means they can't be much larger. For instance, insects have an exoskeleton which would become too heavy for large animals to carry. Also, insects supply oxygen to their cells through a series of tubes that carry air to all body tissues. Larger animals cannot use this approach. They depend on blood in a circulatory system to supply the oxygen needed by tissues.

To insects being small in indeed beautiful. it is a key to the success of these creatures. How successful are they? In the United States it has been estimated that insects average about 400 pounds per acre compared to the weight of humanity of only 14 pounds per acre. They may be small, but what they lack in size, they make in numbers!

 

Writer: Tom Turpin
Editor: Elaine Lambert