OCTOBER
1988

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

10-31-88

Where Have All The Insects Gone?

Each year as fall marches uncontrollably toward winter, nature prepares. Temperatures begin to drop and so do the leaves from trees. Waterfowl wing overhead in their annual southern migration from breeding grounds in the north. Swallows, bluebirds, and redwing blackbirds depart to make way for the birds of winter.

And the insects disappear. Yes, the teeming hoards of insects that occupied every nook and cranny just a few weeks ago are seen no more. The cricket, the cicada and even the mosquito have fallen silent.

To borrow, and slightly modify, a line from an old Peter, Paul and Mary song, "Where have all the insects gone, long time passing?" If the answer is "to graveyards every one," it is a bit misleading. To be sure, many of the insects of last summer have died. But their offspring shall return!

Insects have solved the problem of winter in several ways. Some hibernate. Lady bird beetles, Mexican bean beetles, bald-faced hornets, yellow jackets and cluster flies are among the many that hibernate as adults. These insects seek sheltered places to gain some protection from the winter. They can be found under rocks, in leaf litter, even under the eaves and in the attics of our homes.

Other insects spend the winter as larvae. The larvae of June beetles, known as white grubs, just dig deeper in the soil as the temperature drops. Many caterpillars, such as the wooly bear, crawl into secluded places for their long winter's naps. Most, however, make some provision to keep from freezing. Some reduce the water content of their bodies and replace it with glycerol, the antifreeze of the insect world.

The European corn borer spends the winter as a larvae in corn stalks. A fact of interest to ice fishermen who frequently dig the borers from their hiding places to use as bait.

Some insects avoid the winter by remaining in the egg stage. The mosquito, corn rootworm and praying mantis leave their eggs out in the cold.

Other insects solve the problem of Midwest winters by leaving. Yes, like some of the human species, they go south for the winter. Many of our insect pests repopulate Midwest areas each spring from breeding grounds in the south. Many aphids, cutworms and armyworms use this strategy for dealing with winter. Another insect that migrates back each year is the Monarch butterfly.

Insects have used a variety of tactics to solve the problem of Indiana winters. While insects may be gone, they should not be forgotten. For next spring, when the temperatures begin to warm, the fire of life will be rekindled in tiny insect hearts everywhere. Like the swallows to Capistrano, they shall return!

 

Writer: Tom Turpin
Editor: Carol McGrew