In this presentation, I will show how I use Drosophila populations to understand the operation of sexual selection on living organisms in the lab as well as in the field. Using an experimental evolution approach, I will show how male mating success in the lab can increase to a point where it even overrides the assortative mating occurring within population, and investigate in detail the evolutionary changes behind this boosted performance. Using microcosms, I will demonstrate how the patterns of sex-specific selection can dramatically change between laboratory and field conditions, showing how studying the action of selection in an ecologically realistic environment can be valuable. Finally, I will illustrate a potential new way of using the action of sexual selection to improve pest management methods against fruit flies, with the aim to increase the field performance of mass-reared males used in sterile insect programs.