Symbiont switching and alternative resource acquisition strategies drive mutualism breakdown
Abstract
Cooperative interactions among species—mutualisms—are major sources of evolutionary innovation. However, despite their importance, two species that formerly cooperated sometimes cease their partnership. Why do mutualisms break down? We asked this question in the partnership between arbuscular mycorrhizal (AM) fungi and their plant hosts, one of the most ancient mutualisms. We analyze two potential trajectories toward evolutionary breakdown of their cooperation, symbiont switching and mutualism abandonment. We find evidence that plants stop interacting with AM fungi when they switch to other microbial mutualists or when they evolve alternative strategies to extract nutrients from the environment. Our results show vital cooperative interactions can be lost, but only if successful alternatives evolve.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- May 2018
- DOI:
- 10.1073/pnas.1721629115
- Bibcode:
- 2018PNAS..115.5229W