Explanations for the evolution of delayed maturity usually invoke trade-offs mediated by growth, but processes of reproductive maturation often continue long after growth has ceased. Here, we tested whether sexual selection shapes the rate of post-eclosion maturation in the fruit fly Drosophila melanogaster. We found that populations maintained for more than 100 generations under a short generation time and polygamous mating system evolved faster post-eclosion maturation and faster egg-to-adult development of males, when compared to...