Dormancy conquers natural selection in unchanging unfavourable environments

Researchers puzzle over questions as to how rare species survive extinction, and why a significant proportion of microbial taxa are dormant. Agent-based modelling by a genetic algorithm provides some answers. First, a weak/rare/lowly-adapted species facing an unchanging, unfavourable environment can obtain significantly higher fitness by resorting to pervasive dormancy. Thereby the probability of extinction is reduced. Second, the extent of fitness-gain is greater when a higher fraction of the population is dormant. Thus, the probability of species survival is greater for higher prevalence of dormancy. In sum, pervasive dormancy enables a weak/rare species enhance the extent of favourable adaptation over time, successfully combating the forces of natural selection. The theory developed here complements extant research that predicts benefits of dormancy only in a changing environment.