Did you know that old female fruit flies are less attractive to male fruit flies than young female fruit flies because they no longer smell sexy? Not being a fruit fly, you've probably never even thought about it. But because you can never have too much knowledge, a group of federally-funded scientists has discovered that it is true. Ah yes, the sweet, sweet smell of youth fades over time.
With the help of funding from the National Institutes of Health, researchers at the Baylor College of Medicine and the University of Michigan, put male fruit flies into a "specially designed holding cell," with two female fruit flies, a young one and an old one. Videos of the "encounters" revealed that the male fruit flies were consistently more attracted to the young female flies.
The scientists suspected that differences in the flies' production of pheromones -- chemicals produced by organisms to communicate with or attract each another through the sense of smell - might be the reason for the results.
To rule out the possibility of plain old "good looks" driving the male flies' choices in whoopee partners, the experiments were conducted in total darkness. Even in the dark, the male flies chose the younger females. But, after the scientists washed the pheromones off the female flies' bodies, the male flies no longer discriminated between young and old female partners.
"This is new because we have direct evidence that the pheromones produced at these different ages affect sexual attractiveness differently," said one of the graduate student researchers in a press release.
Bottom line, the researchers concluded that both male and female fruit flies become less alluring with age, with reduced pheromone production being one reason. Does the same thing apply to people? Could be.
"We know that aging is conserved across species," said another scientist. "We want to examine the exciting possibility that the mechanisms underlying attractiveness are also conserved across species."
A synopsis of the researchers' report can be viewed online in The Journal of Experimental Biology.
Photo: Fruit Flies -- Jack Dykinga/USDA