OCTOBER
2003

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

10-23-03

Download the audio of On Six Legs: MP3, WMV.

Termite Queens are the Methuselahs of the Insect World


How long do insects live? A question frequently asked by people who encounter insects in their lives. And, the answer is, "It depends!" It depends on a lot of things. Things like type of insect, the specific stage of development, what food is available and the temperatures of the environment.

Most insects live relatively short lives--partially because they seldom live out their lives. A high percentage of insects don't die a natural death. They are killed by weather, predators or accidents, like flying into a car or a bug zapper.

But even if an insect manages to die of old age, it generally will not have lived for more than a year. Annual life cycles are common in the insect world. That is primarily due to the cold-blooded nature of insects, which does not allow them to function in cold weather.

So the general rule in nature is that the life of an insect from egg to death takes a year or less. For example, grasshoppers lay eggs in the fall that remain in the soil over the winter. In the spring, the eggs hatch, and by August the grasshoppers have reached the adult stage. They mate, lay eggs and then die before winter. The same is true of praying mantids, katydids and crickets,

Boxelder bugs also live for about a year, but they spend the winter as adults. In the case of that nasty pest, the Japanese beetle, it is the grub that survives the winter, but the total life of the insect is about a year.

Those aquatic insects known as Mayflies, or fishflies, also have an annual life cycle. The Mayfly adult life is the shortest in the insect world. It lives for only a day. But during the one day that they live, Mayflies manage to mate and lay eggs.

For some insects, their total life is less than a year. If the species completes more than one life cycle during the growing season, individual insects have a very short life span. Some aphids, plant pests sometimes called plant lice, can complete a generation in less than two weeks. How do they do that? Well, some aphids give birth to live young without mating. They cut out the need for mating--and the need for males--and time spent in the egg stage.

Some honey bees also have a relatively short life. Males, called drones, only live about six weeks from egg to death. During the summer, workers also have a short life--about nine weeks. However, the workers that live in the colony over the winter will have an adult life of about a year in length.

Many insects spend more time in the immature stage than in the adult stage. Some white grub larvae live for 3 years in the soil, others for 5 years. In these cases, the adults live for about two months.

The longest-lived immature insect is the cicada. The immature of the periodical cicada spends 17 years underground feeding on the sap of a tree. Then, it emerges and crawls out of its last immature exoskeleton to seek a mate. During it's short adult life of about two weeks, it doesn't even feed. But it does sing and find a mate!

The longest lives of insects belong to social insects. Not all social insects, but the queen of the social insects. Honey bee queens can live up to seven years. Some ant queens live several years as well. But the champions of all insects, in length of life, are termite queens. The mound-building termites of Africa can live up to 60 years!

As we all know, women live longer than men. This is even true in the insect world. Move over, Noah, with your 950 years, and Methuselah, with your 995 years. Here comes the queen of termites. She lives 3,600 human years, relatively speaking!

 

 

Writer: Tom Turpin
Editor: Olivia Maddox