Two waves of adaptation: speciation induced by dormancy in a model with changing environment

TL;DR

This paper models how dormancy and seasonal changes in environment can lead to two waves of adaptation, potentially causing speciation in populations facing fluctuating conditions.

Contribution

It introduces a population model showing that dormancy combined with seasonal environmental changes can induce speciation through repeated adaptation waves.

Findings

Dormancy allows survival during less favorable seasons.

Two waves of adaptation emerge in the population.

Dormancy can lead to speciation in fluctuating environments.

Abstract

We consider a population model in which the season alternates between winter and summer, and individuals can acquire mutations either that are advantageous in the summer and disadvantageous in the winter, or vice versa. Also, we assume that individuals in the population can either be active or dormant, and that individuals can move between these two states. Dormant individuals do not reproduce but do not experience selective pressures. We show that, under certain conditions, over time we see two waves of adaptation. Some individuals repeatedly acquire mutations that are beneficial in the summer, while others repeatedly acquire mutations that are beneficial in the winter. Individuals can survive the season during which they are less fit by entering a dormant state. This result demonstrates that, for populations in fluctuating environments, dormancy has the potential to induce speciation.