Spatiotemporal ecological chaos enables gradual evolutionary diversification without niches or tradeoffs
Abstract
Ecological and evolutionary dynamics are intrinsically entwined. On short timescales, ecological interactions determine the fate and impact of new mutants, while on longer timescales evolution shapes the entire community. Here we study the evolution of large numbers of closely related strains with generalized Lotka Volterra interactions but no niche structure. Host-pathogen-like interactions drive the community into a spatiotemporally chaotic state characterized by continual, spatially-local, blooms and busts. Upon the slow serial introduction of new strains, the community diversifies indefinitely, accommodating an arbitrarily large number of strains in spite of the absence of stabilizing niche interactions. The diversifying phase persists - albeit with gradually slowing diversification - in the presence of general, nonspecific, fitness differences between strains, which break the assumption of tradeoffs inherent in much previous work. Building on a dynamical-mean field-theory analysis of the ecological dynamics, an approximate effective model captures the evolution of the diversity and distributions of key properties. This work establishes a potential scenario for understanding how the interplay between evolution and ecology - in particular coevolution of a bacterial and a generalist phage species - could give rise to the extensive fine-scale diversity that is ubiquitous in the microbial world.
Data availability
The current manuscript is a computational study, so no data have been generated for this manuscript. Simulations use only standard algorithms: details in paper.
Article and author information
Author details
Funding
National Science Foundation (PHY-160760 and PHY-2210386)
- Aditya Mahadevan
- Michael T Pearce
- Daniel S Fisher
National Institutes of Health (R01AI13699201)
- Aditya Mahadevan
- Daniel S Fisher
Simons Foundation (Sabbatical Fellowship)
- Daniel S Fisher
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Armita Nourmohammad, University of Washington, United States
Publication history
- Received: August 16, 2022
- Accepted: April 27, 2023
- Accepted Manuscript published: April 28, 2023 (version 1)
Copyright
© 2023, Mahadevan et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Further reading
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- Ecology
- Evolutionary Biology
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- Ecology
- Evolutionary Biology
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