Adaptive reproductive strategies

When in its life should an individual first attempt to reproduce? How often should it breed thereafter? How much effort should it invest in each attempt? And does this vary between individuals in the same population? These questions are central to the many studies investigating adaptive life-history strategies, across the taxonomic spectrum, yet detailed answers are provided by few, particularly in large, free-ranging species. This is because comprehensive data on the costs and benefits of reproduction throughout life are essential for the task, but are difficult to collect in the wild, especially for males in polygynous species. With Soay sheep, however, we have the detailed information with which to investigate the reproductive benefits and costs for both sexes, and the way these vary with the environment and individual phenotype.