Directional selection and the evolution of breeding date in birds.

  title={Directional selection and the evolution of breeding date in birds.},
  author={T. Douglas Price and Mark Kirkpatrick and Stevan J. Arnold},
  volume={240 4853},
In many bird species, those pairs that breed earlier in the season have higher reproductive success than those that breed later. Since breeding date is known to be heritable, it is unclear why it does not evolve to an earlier time. Under assumptions outlined by Fisher, a model is developed that shows how breeding date may have considerable additive genetic variance, appear to be under directional selection, and yet not evolve. These results provide a general explanation for a persistent… CONTINUE READING