AUGUST
2003

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

08-14-03

Some Insects are Fly-by-Nighters

Scientists like to divide things into groups. This process is called classification. For instance, things on the earth could be grouped as living or nonliving. Biologists divide living things into either plant or animal. Animals can be further divided into vertebrates and invertebrates, depending on the presence or absence of vertebrae. And so the process goes.

This scientific activity has been going on for a long time. Even the earliest humans probably classified things into groups. Certainly the ancient Greek philosopher Aristotle developed classification schemes. He based his system for animals on whether or not the creature produced external eggs.

Living things can be grouped according to aspects of their biology. Plants are called annual or perennial depending on how long they live. Animals can be classified according to the times when they are active. Those active during daylight hours are diurnal while the night-active ones are nocturnal. Some are active only at twilight and are called crepuscular animals.

Humans are diurnal animals. We need light to function. But, unlike other diurnal animals, humans have created artificial light to extend the time when activity can occur. So, even though we call some people night owls, it is in name only since human night owls need light.

Real owls, on the other hand, are adapted to life after dark. So are many other animals, including bats, cats and rats. Many insects are also active during the night.

Some of the best-known nocturnal insects are moths. In fact, most species of moths are night active. As moths go about their nightly insect business, finding food and mates mostly, they sometimes end up near lights. That is the reason lighted windows and porch lights become moth gathering places.

Many of the moths that accumulate around lights are small and dull-colored. But a few are more spectacular. Some are quite large and are known as the giant silkworm moths. This includes the Promethea, Polyphemus and Luna moths.

Some of the moths that are found around lights have brightly colored hind wings. The front wings of these moths are generally dull-colored Because of the difference in color patterns of the wings these generally known as underwing moths. When these moths are at rest the bright wings are hidden by the dull-colored fore wings.

Underwing moths will use the bright colors of the hind wing to scare predators. Sudden exposure of the bright hind wing serves to frighten potential predators. Some moths have hind wings that are colored to look like the eye of an animal, such as a snake or owl. The exposure of such eyespots will startle an unsuspecting animal and might allow the moth to escape becoming a meal.

Many beetles are also night flyers. We are all familiar with the fireflies. Fireflies are soft-winged beetles and fly at night using their light to attract a mate. Several species of beetles known as Junebugs also are active night flyers. These are the insects that we hear crashing into lighted windows.

Some species of leafhoppers also fly around during the nighttime hours. Leafhoppers are small insects. Some species are small enough to come through the mesh of a window screen and end up in our light fixtures along with numerous small beetles.

So next time you are removing those night-acquired bug splats from your car windshield, remember this. Chances are good that the fly-by-night insect was either a beetle or a moth.

 

Writer: Tom Turpin
Editor: Olivia Maddox