Restricting mutualistic partners to enforce trade reliance

• Published in: Nature communications 2016-01, Vol.7 (1), p.10322-10322, Article 10322
• Main Authors: Wyatt, Gregory A. K., Kiers, E. Toby, Gardner, Andy, West, Stuart A.
• Format: Article
• Language: English
• Subjects: 631/158/853; 631/181/2481; Fungi - physiology; Humanities and Social Sciences; Models, Biological; multidisciplinary; Mycorrhizae - physiology; Plant Physiological Phenomena; Plants - microbiology; Science; Science (multidisciplinary); Symbiosis
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms10322

Mutualisms are cooperative interactions between members of different species, often involving the trade of resources. Here, we suggest that otherwise-cooperative mutualists might be able to gain a benefit from actively restricting their partners’ ability to obtain resources directly, hampering the ability of the restricted partner to survive and/or reproduce without the help of the restricting mutualist. We show that (i) restriction can be favoured when it makes the resources of the restricting individual more valuable to their partner, and thus allows them to receive more favourable terms of trade; (ii) restriction maintains cooperation in conditions where cooperative behaviour would otherwise collapse; and (iii) restriction can lead to either an increase or decrease in a restricted individual’s fitness. We discuss the applicability of this scenario to mutualisms such as those between plants and mycorrhizal fungi. These results identify a novel conflict in mutualisms as well as several public goods dilemmas, but also demonstrate how conflict can help maintain cooperation. Mutualistic interactions involve trading benefits between cooperative species. Here, the authors show that restricting the resource acquisition of a mutualistic partner can increase mutualism by promoting resource trade, which suggests that conflict may lead to increased cooperation.