Discussion
Our results show that individual generation time measured as the mean age at reproduction summarizes the pace of an individual’s life-history and has the potential to evolve in response to ecological pressures. Male generation time was longer compared to females due to sex differences in age-dependent reproduction and survival, likely caused by differences in competitive regimes. We also found that in years where competition was higher and average fitness was lower, recruit production was lower and older individuals contributed relatively more to population growth. In contrast, when populations were growing, younger individuals contributed disproportionately more to population growth. These results imply that fluctuations in competitive regimes associated to population sizes, influence the mean age at reproduction, thereby affecting the demographic characteristics of this metapopulation.