The role of demographic stochasticity in a speciation model with sexual reproduction

TL;DR

This paper investigates how demographic stochasticity influences phenotypic clustering and potential speciation in sexually reproducing organisms, revealing that noise can induce clustering even when deterministic models predict homogeneity.

Contribution

It demonstrates that demographic stochasticity can lead to phenotypic clustering in sexual reproduction models, expanding understanding beyond deterministic predictions.

Findings

Noise induces phenotypic clusters where deterministic models predict uniformity.

Demographic stochasticity significantly affects phenotypic distribution in sexual reproduction models.

Stochastic effects can sometimes override deterministic outcomes in speciation processes.

Abstract

Recent theoretical studies have shown that demographic stochasticity can greatly increase the tendency of asexually reproducing phenotypically diverse organisms to spontaneously evolve into localised clusters, suggesting a simple mechanism for sympatric speciation. Here we study the role of demographic stochasticity in a model of competing organisms subject to assortative mating. We find that in models with sexual reproduction, noise can also lead to the formation of phenotypic clusters in parameter ranges where deterministic models would lead to a homogeneous distribution. In some cases, noise can have a sizeable effect, rendering the deterministic modelling insufficient to understand the phenotypic distribution.