August 12, 2011
The houbara bustard is a large brown-and-white bird found in the deserts of North Africa, Asia and the Middle East. For six months of the year, for 18 hours a day the males of the species carry out an elaborate display hoping to win the ladies, as outlined in a recent paper in Ecology Letters:
After an initial period of pre-display strutting, males erect an ornamental ‘shield’ of long white feathers in front of them as they begin to run at high speed, often circling a rock or bush. This display culminates in a flash of both black and white ornamental feathers and is often accompanied by several subsonic ‘booming’ calls.
Over the six months, males can lose up to 10 percent of their body weight. But that’s not the only price for keeping up these elaborate displays. That paper in Ecology Letters shows that the guys who are most sexually extravagant—the ones trying to hardest to get the girls—experience aging faster, with their sperm quality declining faster than that of other males.
Females mate with multiple males, so in addition to displays, the males have to invest in producing large quantities of high-quality sperm that can win out in the competition (inside the female) that follows copulation. And when the males are young, the more elaborate their display, the better their sperm. But that changes when they reach about four years of age, the researchers found in their new study. The males continue their extravagant daily displays, but their sperm quality takes a hit. They produce less sperm and their ejaculates contains more dead and abnormal sperm than males that didn’t put as much effort into attracting the ladies.
“This is the bird equivalent of the posers who strut their stuff in bars and nightclubs every weekend,” says study lead author Brian Preston, of the University of Burgundy in France. “If the bustard is anything to go by, these same guys will be reaching for their toupees sooner than they’d like.”
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