Competition between species can stabilize public‐goods cooperation within a species

Molecular Systems Biology

Hasan Celiker¹ 

[1] Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA

关键词: cooperation;    ecology;    evolution;    interspecies competition;   

DOI  :  10.1038/msb.2012.54

来源: Wiley

【 摘 要 】

Abstract

Competition between species is a major ecological force that can drive evolution. Here, we test the effect of this force on the evolution of cooperation within a species. We use sucrose metabolism of budding yeast, Saccharomyces cerevisiae, as a model cooperative system that is subject to social parasitism by cheater strategies. We find that when cocultured with a bacterial competitor, Escherichia coli, the frequency of cooperator phenotypes in yeast populations increases dramatically as compared with isolated yeast populations. Bacterial competition stabilizes cooperation within yeast by limiting the yeast population density and also by depleting the public goods produced by cooperating yeast cells. Both of these changes induced by bacterial competition increase the cooperator frequency because cooperator yeast cells have a small preferential access to the public goods they produce; this preferential access becomes more important when the public good is scarce. Our results indicate that a thorough understanding of species interactions is crucial for explaining the maintenance and evolution of cooperation in nature.

Synopsis

Cooperative phenotypes are found to be favored in a yeast population grown in the presence of a bacterial species. The bacteria drive cooperation within yeast by competing for essential resources and by limiting the access of cheaters to the public goods produced by cooperating yeast cells.

• Presence of bacteria selects for cooperator phenotypes within a yeast population.
• Bacteria limit yeast population density, forcing the yeast populations to spend more time in low-density conditions that favor cooperators.
• Bacteria deplete glucose produced by cooperator yeast cells and limit cheaters’ access to free glucose.
• These mechanisms favor cooperator yeast cells, because cooperators have preferential access to a small fraction of the public goods they produce. When competing against bacteria, this small access becomes important and gives an advantage to the cooperator cells over the cheater cells.

【 授权许可】

CC BY-NC-SA   
Copyright © 2012 EMBO and Macmillan Publishers Limited

Creative Commons Attribution License, which permits distribution, and reproduction in any medium, provided the original author and source are credited. This license does not permit commercial exploitation without specific permission.