Are Mutualisms Maintained by Host Sanctions or Partner Fidelity Feedback?

Proceedings of the National Academy of Sciences

Posted: 2 Apr 2010 Last revised: 5 Sep 2012

See all articles by E. Glen Weyl

E. Glen Weyl

Microsoft Research New York City; RadicalxChange Foundation

Megan E. Frederickson

Harvard University - Society of Fellows; University of Toronto - Department of Ecology & Evolutionary Biology

Doug W. Yu

Chinese Academy of Sciences (CAS)

Naomi E. Pierce

Harvard University - Society of Fellows

Date Written: August 10, 2010

Abstract

Although mutualisms are common in all ecological communities and have played key roles in the diversification of life, our current understanding of the evolution of cooperation applies mostly to social behavior within a species. A central question is whether mutualisms persist because hosts have evolved costly punishment of cheaters. Here, we use the economic theory of employment contracts to formulate and distinguish between two mechanisms that have been proposed to prevent cheating in host-symbiont mutualisms, Partner Fidelity Feedback (PFF) and Host Sanctions (HS). Under PFF, positive feedback between host fitness and symbiont fitness is sufficient to prevent cheating; in contrast, HS posits the necessity of costly punishment to maintain mutualism. A coevolutionary model of mutualism finds that HS are unlikely to evolve de novo, and published data on legume-rhizobia and yucca-moth mutualisms are consistent with PFF and not HS. Thus, in systems considered to be textbook cases of HS, we find poor support for the theory that hosts have evolved to punish cheating symbionts; instead, we show that even horizontally transmitted mutualisms can be stabilized via PFF. PFF theory may place previously underappreciated constraints on the evolution of mutualism, and explain why punishment is far from ubiquitous in nature.

Keywords: mutualism, principal-agent, moral hazard, evolution of cooperation

JEL Classification: D82, A12

Suggested Citation

Weyl, Eric Glen and Frederickson, Megan E. and Yu, Doug W. and Pierce, Naomi E., Are Mutualisms Maintained by Host Sanctions or Partner Fidelity Feedback? (August 10, 2010). Proceedings of the National Academy of Sciences. Available at SSRN: https://ssrn.com/abstract=1582717

Eric Glen Weyl (Contact Author)

Microsoft Research New York City ( email )

641 Avenue of the Americas
7th Floor
New York, NY 10011
United States
8579984513 (Phone)

HOME PAGE: http://www.glenweyl.com

RadicalxChange Foundation ( email )

HOME PAGE: http://www.radicalxchange.org

Megan E. Frederickson

Harvard University - Society of Fellows ( email )

1875 Cambridge Street
Cambridge, MA 02138
United States

University of Toronto - Department of Ecology & Evolutionary Biology ( email )

Toronto, Ontario M5S 3G8
Canada

Doug W. Yu

Chinese Academy of Sciences (CAS) ( email )

52 Sanlihe Rd.
Datun Road, Anwai
Beijing, Xicheng District 100864
China

Naomi E. Pierce

Harvard University - Society of Fellows ( email )

1875 Cambridge Street
Cambridge, MA 02138
United States

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