Sex as information processing: optimality and evolution

TL;DR

This paper extends models of evolutionary information processing to sexual reproduction, analyzing conditions for its advantage and the role of dimorphism, using an analytical approach within the infinitesimal model of quantitative genetics.

Contribution

It provides a general analytical framework for understanding the evolution of sexual reproduction and dimorphism in variable environments, extending previous asexual models.

Findings

Sexual reproduction can be advantageous under certain environmental conditions.

Sexual dimorphism may be adaptive but often does not outweigh its costs.

The model unifies previous analyses and applies to diverse ecological scenarios.

Abstract

The long-term growth rate of populations in varying environments quantifies the evolutionary value of processing the information that biological individuals inherit from their ancestors and acquire from their environment. Previous models were limited to asexual reproduction with inherited information coming from a single parent with no recombination. We present a general extension to sexual reproduction and an analytical solution for a particular but important case, the infinitesimal model of quantitative genetics which assumes traits to be normally distributed. We study with this model the conditions under which sexual reproduction is advantageous and can evolve in the context of autocorrelated or directionally varying environments, mutational biases, spatial heterogeneities and phenotypic plasticity. Our results generalize and unify previous analyses. We also examine the proposal made by Geodakyan that the presence of two phenotypically distinct sexes permits an optimal adaptation to varying environments. We verify that conditions exists where sexual dimorphism is adaptive but find that its evolutionary value does not generally compensate for the two-fold cost of males.