Games of multicellularity

TL;DR

This paper introduces a new population structure inspired by simple multicellular organisms, analyzing evolutionary game dynamics within cell complexes and deriving conditions for strategy selection, extending previous models to include frequency-dependent interactions.

Contribution

It presents a novel multicellular-inspired population structure and derives exact conditions for strategy selection, generalizing the sigma condition to complex sizes beyond two.

Findings

Exact conditions for strategy favorability derived for all complex sizes at weak selection.

Main results extend the sigma condition symmetry to multicellular structures.

Model applies to various two-strategy games like prisoner's dilemma and hawk-dove.

Abstract

Evolutionary game dynamics are often studied in the context of different population structures. Here we propose a new population structure that is inspired by simple multicellular life forms. In our model, cells reproduce but can stay together after reproduction. They reach complexes of a certain size, n, before producing single cells again. The cells within a complex derive payoff from an evolutionary game by interacting with each other. The reproductive rate of cells is proportional to their payoff. We consider all two-strategy games. We study deterministic evolutionary dynamics with mutations, and derive exact conditions for selection to favor one strategy over another. Our main result has the same symmetry as the well-known sigma condition, which has been proven for stochastic game dynamics and weak selection. For a maximum complex size of n=2 our result holds for any intensity of selection. For n > 2 it holds for weak selection. As specific examples we study the prisoner's dilemma and hawk-dove games. Our model advances theoretical work on multicellularity by allowing for frequency-dependent interactions within groups.