Older flies with sexy smell turn on males

U. MICHIGAN (US) — Changes in pheromone production that occur with age can reduce sexual attractiveness, according to a recent study with fruit flies.

Pheromones are chemicals produced by an organism to communicate or attract another. The new study, published in the Journal of Experimental Biology, examined how pheromones play a role in the sexual attractiveness and aging process of the common fruit fly, Drosophila melanogaster, says Scott D. Pletcher, senior author of the study, associate professor in the department of molecular and integrative physiology at the University of Michigan.

Researchers first showed that older flies were significantly less attractive than younger flies. They then discovered that the profiles of different pheromones that flies produce, called cuticular hydrocarbons, change with age.



Using a specially designed holding arena, researchers introduced a male fly into a chamber that contained two females—a young fly and an old fly. The females were decapitated, to eliminate the chances they’d influence the male fly with their behavior.

Researchers used state-of-the-art video tracking software to accurately assess the behavior of the male fly. Those videos showed that the male was much more attracted to the young fly. Similar experiments revealed that the same was true for females; they preferred younger males.

But later, researchers later removed the pheromones on young and old flies. They reapplied either pheromones from young or old flies to those blank flies and found that the choosing males preferred flies covered with the young pheromone.

“Our research showed this attractiveness was driven by the production of this cuticular hydrocarbon,” says Pletcher. “We found in the end that regardless of the age of the fly, the choosing flies really went crazy for the flies that carried the young pheromone.”

Because the fruit flies live just 60 to 90 days, they are a powerful tool for studying aging. As they age, their appearance does change. These results are important for studying what impacts the fruit fly lifespan.

“This is new because we have direct evidence that the pheromones produced at these different ages affect sexual attractiveness differently,” says Tsung-Han Kuo , a graduate student in the department of molecular and human genetics and the Huffington Center on Aging at Baylor College of Medicine who was the first author of the report.

This doesn’t mean there’s hope that fruit fly pheromone is a love potion to attract a mate before Valentine’s Day, Pletcher says, but it does provide some exciting insight into whether there is a connection between attractiveness and health.

“We’re excited about these results because they may help us leverage our knowledge of the mechanisms that drive the aging process. This research indicates that the mechanisms important for aging also influence outward attractiveness,” Pletcher says.

“Our hope is we can take a trait like attractiveness and study the connection between attractiveness and health.”

Researchers from Baylor College of Medicine, the National University of Singapore, and the University of Münster contributed to the work. Funding was provided by the National Institutes of Health; the Glenn Foundation; the American Federation for Aging Research; the Ellison Medical Foundation; the Alexander von Humboldt Foundation; the Singapore National Research Foundation; the National Institute of General Medical Sciences; the Drosophila Aging Core of the Nathan Shock Center of Excellence in the Biology of Aging funded by the National Institute on Aging and the National Science Foundation.

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