Mutualisms, in which different species interact in close proximity and provide resources, services and other benefits to each other, are widespread in nature, occurring in every kingdom of life and in every biome. However, natural selection is expected to favor exploitation over cooperation because individuals that derive benefits from a mutualistic partner can maximize their own fitness by avoiding the costs of cooperation. Thus, explaining the persistence of mutualisms is challenging. For instance, the mycorrhizal symbiosis is one of the most widespread mutualisms in nature, yet several plant lineages have abandoned it by evolving the ability to exclude mycorrhizal fungi from their roots. Using phylogenetic information to reconstruct ancestral states as well as artificial selection studies in contemporary populations, our lab is exploring why the symbiosis is maintained as a mutualism in some cases, yet is abandoned in other contexts.
Related publications (*Undergraduate, †Graduate or #Postdoctoral advisee) :
Maherali H., Oberle B., Stevens P.F., Cornwell W.K., McGlinn D.J. 2016. Mutualism persistence and abandonment during the evolution of the mycorrhizal symbiosis. American Naturalist, 188: E113-E125.
Maherali H. 2014. Is there an association between root architecture and mycorrhizal growth response? New Phytologist, 204:192-200.