Data from: Sexual selection shapes development and maturation rates in Drosophila

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 populations kept under short
generations and randomized monogamy that eliminated sexual selection. An
independent assay demonstrated that more mature males have higher fitness
under polygamy, but this advantage disappears under monogamy. In contrast,
for females greater maturity was equally advantageous under polygamy and
monogamy. Furthermore, monogamous populations evolved faster development
and maturation of females relative to polygamous populations, with no
detectable trade-offs with adult size or egg-to-adult survival. These
results suggest that a major aspect of male maturation involves developing
traits that increase success in sexual competition, whereas female
maturation is not limited by investment in traits involved in mate choice
or defense against male antagonism. Moreover, rates of juvenile
development and adult maturation can readily evolve in opposite directions
in the two sexes, possibly implicating polymorphisms with sexually
antagonistic pleiotropy.