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A female mallard duck that is allowed to choose its own preferred mate has ducklings that survive infancy better than the offspring of a pair in which the female is matched with an unwanted male, according to a new test. Pairing the female with her first choice, instead of with a reject, raised duckling survival by about a third, reports Cynthia Bluhm of the Delta Waterfowl Research Station in Manitoba, Canada. 5 What specific survival advantages actually come from a female’s choosing her mate “is a very basic question that we don’t know the answer to”, Bluhm says. Though Charles Darwin argued that female choice wielded great power in evolution (a phenomenon known as ‘sexual selection’), “nobody believed him for about 100 years,” Bluhm explains. Even when researchers started testing the idea, she notes, their experiments focused on whether feminine choice forced 10 the evolution of male characteristics such as the peacock’s tail, and whether such ornaments honestly identified males that would father the healthiest young. Bluhm raised a colony of captive ducks from eggs she collected in the wild. She then showed each of the 70 females three different males. When females showed a clear preference for one particular male, she allowed that pair to mate. Half the females chose their own mate, and the 15 other half were paired with rejected males. “I didn’t use any obviously inferior males”, Bluhm says. She also gave the ducks special care, protecting them from predators and keeping their eggs in an incubator. “It was a very conservative experiment”, Bluhm says. Seeing duckling survival under such protective conditions suggests to her that the effects of sexual selection would be even more dramatic in the real world. 20

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