Only the Flirts Die Young

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Flirting is fun, but it can be costly – at least, when you try too hard. In the case of one rather unfortunate North African bird, too much flirting actually causes faster aging. The more the spunky male Houbara bustards use their flamboyant mating tactics – which involve flared-up feathers and somewhat manic running around – the quicker they pass their reproductive prime years, according to a study led by biologist Brian Preston of the University of Burgundy in France.

“The bustard shows that an over-abundance of early reproductive effort comes at the cost of physiological declines later in life,” Preston said in a statement. Because the displays are so extravagant – see the video below for proof – they are energetically expensive, and thus cause what is essentially an early sperm burnout in male bustards. These fatigued birds begin to produce smaller ejaculates with higher numbers of dead and abnormal sperm far earlier than their more passive peers.


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Preston’s team looked at over 1,700 bustards, taking note of the number of days on which they performed their come-hither walks and calls as well as collecting and examining their ejaculate from copulation with a dummy female. The animals that displayed for a longer time at younger ages continued this behavior in later life – which ought to lead to greater reproductive success – but these Casanovas actually showed an 85% reduction in sperm production in their twilight years. And the little sperm they did produce didn’t do much good either, because most of it had defects such as double heads, double tails or immotility.

Why this display-related senescence, or biological aging, happens is still not clear; the scientists are unsure why the genes that promote this result have yet to be eliminated. “The reason why an organism should senesce has been an evolutionary puzzle, as natural selection would be expected to ‘weed-out’ the genes responsible for these age-related declines,” Preston said. “Evolutionary biologists have put forth the idea that the ‘riskiness’ of life – with all its predators, natural disasters and the like – means that an animal may never get to express certain genes later on in their lives. This may make them ‘overspend’ their energy early on, even such behavior will be detrimental to the creature later.

And then there is what we’d all really like to know: could Preston’s findings translate to humans? The scientists aren’t too sure, but they have ideas. “This is the bird equivalent of the posers who strut their stuff in bars and nightclubs every weekend,” Preston said. “If the bustard is anything to go by, these same guys will be reaching for their toupees sooner than they’d like.” The jury may still be out on this one, but “don’t overdo it,” is probably good advice  –  whether you’re a man or a bird.

Tara Thean is a TIME contributor. Find her on Twitter at @TaraThean. You can also continue the discussion on TIME‘s Facebook page and on Twitter at @TIME.

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