OCTOBER
1996

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

10-10-96

First In Flight

Humans in today's world are obsessed with the concept of No. 1. From popular songs and football teams to best cities in which to live, being ranked first is the ultimate mark of success. We admire people who are first to climb a mountain, first to reach a sales goal or first in their graduating class. All of this, of course, is when we compare ourselves to other humans.

When we compare ourselves biologically to other animals, we seldom top the list. There is very little we can do that some other group of animals can't do better. Much better! Take flight, for instance. Long before the brothers Wright coaxed their airplane off the ground, and well before birds had flapped their way into the wild blue yonder, insects were master aerialists.

The ability to fly is one of the reasons insects are such successful animals. Most adult insects have wings, although there are some exceptions. For instance, fleas and lice are wingless, as are most ants and termites. Ants and termites do, however, produce wings during their reproductive stages. 

In recognition of their aerial ability, members of one entire group of insects, the order Diptera, are called flies. Among these aptly named creatures are house flies, deer flies, horse flies and fruit flies. True flies have only one pair of wings. All other flying insects have four wings. Some of the four-winged insects also have the word fly in their name, including the dragonflies, damselflies, butterflies, and dobsonflies, but scientifically these insects aren't flies, even though they fly.

In general, insects get airborne by moving their wings up and down. In comparison to flying machines of humans, insect flight is more like that of a helicopter than a fixed-wing plane. The speed with which insects can vibrate their wings is remarkable — hundreds of times per second. To understand how fast insects move their wings, consider that hummingbirds beat their wings about 50 times per second. Only a few insects, some butterflies and moths, flap their wings at a slower rate than the hummingbird.

The hummingbird gets its name from the sound produced by wing vibrations. Insects also produce sound when they fly. Many beetles have a low-pitched hum with wing-beat frequencies of 50 to 90 per second. Hornets, with 110 beats per second, have a lower hum than honey bees with their 250-beat frequency. The mosquito produces that annoying high-pitched sound by vibrating its wings at around 300 times per second. Some midges vibrate their wings at more than 1,000 times per second, producing a very high-pitched, almost inaudible sound.

Many butterflies fly along at only 8 beats per second and don't produce any sound at all. Unless you can believe some cartoonists who depict butterfly flight with the words, flap, flap, flap!

 

Writer: Tom Turpin
Editor: Andrea McCann