By Marsha Walton
CNN

(CNN) -- A tiny fly with an unusual home is helping scientists get a first-ever look at how insects in the wild grow old.

"Insects are the most important study system for aging," said Russell Bonduriansky, whose research is published in this week's issue of the journal Nature. "It's unlikely we'll ever reverse or stop the aging process, but the unique ecology of the antler fly can help us understand why we age."

The antler fly, found in eastern Canada, breeds exclusively on the discarded antlers of a deer or moose. Because its adult lifespan is just a few days in the wild, and because of the limited area that makes up its habitat (an antler and some nearby vegetation) researchers were able to physically mark and track the activities of individual insects throughout their lives.

Scientists say antler flies are on an evolutionary mission during their very short life span, to survive long enough to reproduce. At just two millimeters long, it's a tough world for the tiny creatures. They can be eaten by spiders or other insects, die in cold temperatures or drown in one drop of water.

Clues to aging?

A discarded deer or moose antler becomes the home and breeding ground for the tiny antler fly.

People may be a lot more complex than antler flies, but they too have certain driving forces that impact how they age.

"One of the secrets of successful aging for humans is to have meaning and purpose in life. If we lack a purpose, if we lack a direction, if we lack meaning in our lives the acceleration of the aging process is palpable," said Dr. Edward Creagan, Professor of Medical Oncology and editor of "The Mayo Clinic on Healthy Aging."

Creagan says the criteria for successful aging is not necessarily the biology or the physiology, but the emotional, spiritual, and social. Many studies, for example, have shown that critically ill people can defy all odds and somehow live to see the birth of a grandchild, the return of a son from military service, the celebration of religious holidays.

"The mind seems to be saying, give me a purpose, a reason, I will find out how to hang on," said Creagan. "In the home stretch of our lives, we need to create purpose, create meaning, or we die."

What did they find?

In their short but driven efforts to reproduce, researchers found male antler flies can be "astonishingly aggressive" said Bonduriansky, attacking much larger flies as they seek out female partners. So it's an important piece of the evolutionary puzzle to learn that some of these insects do survive long enough that their vital functions start to deteriorate, and even in the wild, they age.

The median survival rate for the 609 male flies studied was six days. Two of the flies studied in Ontario's Algonquin Park earned the title "superflies," living 32 days. And they mated or tried to mate each day.

The researchers say it's important that the flies start out their mating search boldly. The older males are not as good at chasing away other males or in courting females.

"The most intense selection is early life, if they can't make it through the first five days it doesn't matter that they might be strong on day 10. First they have to survive to day 10," said Chad Brassil, also an evolutionary ecologist at the University of Toronto.

Mating for hours

Males spend a great amount of time and energy fighting each other over females.

And while some species of flies complete their mating ritual in a minute or two, antler flies spend two to two and a half hours mating. There's likely an evolutionary reason why the antler flies take longer than other types of flies, Brassil said.

Antler flies, some birds, and horseshoe crabs are among animals whose males stay on top of the female after copulation.

"There's some evidence that the last male to mate with a female is the father of the progeny. So if a male wants to guarantee that, he'll stay and 'guard' the female," said Brassil. "I can't help but ponder the human equivalent. The big guy at the end of the bar who makes it clear who his woman is."

All the energy that the flies spend defending their territory and seeking out a mate may contribute to the aging process. There is a simultaneous decline in survival and reproduction. The aging process, or senescence, is likely a combination of the fighting, the mating and the wearing out of the body.