The male Houbara bustard of North Africa is one of the animal kingdom's most extravagant creatures, with huge ornamental feathers and complex, energetic mating practices known as "booming." But all that booming has dire consequences for their actual reproductive chances.
Booming is a highly elaborate display meant to attract a mate, and it takes a lot out of the males - starting, disturbingly enough, with their sperm count. According to a recent ten-year study of over 1,700 Houbara bustards, those birds that did the most booming were consistently the least fertile. And it wasn't that the bustards were compensating for a deficiency they had been born with. Rather, it was the displays themselves that seemed to sap the life out of the males.
Lead researcher Dr. Brian Preston of France's University of Burgundy explains the fate of these males:
"Over the age of six years. They began to produce much smaller ejaculates with immobile and frequently abnormal sperm. But the key finding was that males that had invested most effort displaying to females in their earlier years experienced the onset of this age-related decline in fertility at a younger age. They effectively seem to 'burn themselves out' sooner."
But the study isn't merely concerned with the sexual horrors of being a bustard - this might actually help us understand some of the evolutionary drivers behind aging. These birds are unusually long-lived, surviving well into their twenties. Considering their long lifespan, it doesn't seem to make much sense that the path to reproductive success - in other words, lots of booming - would cause such deterioration so early in their lives.
Dr. Preston argues that it's all about evolutionary trade-offs. There's no point in being fit and active at 20 if you can't survive past the age of 5. As such, animals may tend to "overspend" in their early years to ensure their short-term survival, even if it's at the expense of their long-term health:
"This is precisely the kind of relationship we have found. Life is risky. Predators, parasites and diseases are likely to prevent animals from living for long periods anyway. So it might be better for them to spend now and not worry about later."
Understanding how those evolutionary trade-offs operate could prove crucial to a more complete knowledge of the aging process. In the meantime, perhaps we can spare a thought for the booming Houbara bustards, who have to be the most ridiculous but strangely poignant example ever of why one can have sex or have one's health...but apparently not both.
Via BBC News.