Natural selection for moderate testosterone surprises scientists
Monday, May 31, 2010 - 22:20
in Biology & Nature
A field study of the relationship between testosterone and natural selection in an American songbird, the dark-eyed junco, has defied some expectations and confirmed others. Scientists report that extreme testosterone production -- high or low -- puts male dark-eyed junco at a disadvantage in both survival and reproduction outside their semi-monogamous breeding pairs.