Modeling and Simulation Group Meeting (hidden)
Eco-Evolutionary Dynamics of Populations in Fluctuating Environments
Speaker: Mauro Mobilia, Professor of Applied Mathematics, University of Leeds
Location: Warren Weaver Hall 1302
Date: Thursday, September 14, 2023, 12:30 p.m.
Synopsis:
Environmental variability greatly influences how the size and composition of a population evolve. In microbial communities, variations of the composition and size of the population, i.e. their eco-evolutionary dynamics, are key to understand the mechanisms of antimicrobial resistance, and may lead to population bottlenecks, where new colonies consisting of few individuals are prone to fluctuations. How the composition and size of these communities evolve is often interdependent, and demographic fluctuations are generally coupled to environmental variability, often resulting in feedback loops and cooperative behavior.
In this seminar, I will focus on a class of simple and insightful models of populations of fluctuating size whose growth is limited by a binary carrying capacity that endlessly switches between values corresponding to abundant and scarce resources. In these models, the population consists of two strains, one growing faster than the other, that compete under various scenarios. In the basic model, the competition is only for the same resources, and one classically expects that the faster strain always prevails (exclusion principle). Using analytical tools and computational means, I will show how the population size distribution and the strains fixation/extinction probability are dramatically influenced by the coupling of demographic fluctuations and environmental variability. In addition to the basic model with random binary switching, the cases of periodic switching and different forms of environmental noise (of discrete and continuous range) will be mentioned. I will then discuss how these ideas and techniques are being generalized to study the eco-evolutionary dynamics of cooperative antimicrobial resistance, as well as the role of twofold environmental variability (toxin concentration and nutrients abundance) on the long-lived coexistence of the strains.
References:
Phys. Rev. Lett.119, 158301 (2017); J. Roy. Soc. Interface 15, 20180343 (2018); Phys. Rev. Lett. 25, 048105 (2020); J. Theor. Biol. 491, 110135 (2020); J. Roy. Soc. Interface 18, 20210613 (2021); Phys. Rev. Research 5, L022004 (2023); bioRxiv 2023.07.06.547929; arXiv:2307.06314