Multispecies communities and dynamics

Keynote talk, Thursday 11th July:

Erida Gjini – Understanding cooperation and competition in co-colonization systems with multiple strains (11:30-12:30)

Explaining the forces generating and shaping diversity in microbial ecosystems remains a fascinating challenge. For this, tractable models are needed, that bridge the gap between pattern observations and underlying mechanisms. In a series of papers, we develop a mathematical modeling framework where colonization systems with multiple interacting strains can be studied. In our model N similar strains grow, propagate and interact in co-colonization via micro-scale environmental modification, which can range from pairwise cooperation to competition. Using time-scale separation, we simplify the model and obtain an explicit replicator equation for strain frequency dynamics. Starting from our original epidemiological motivation, I will present this framework and highlight some key mathematical and biological features that enhance our understanding of multi-strain microbial consortia. Applications may range from epidemiology and coinfection dynamics, to microbiota or social evolution.

Contributed talks, Thursday 11th July:

Jonathan Aagren – Using the Lotka-Volterra competition model to predict co-existence from extinction (12:30-12:55)

Samraat Pawar – Predicting the assembly and functioning of bacterial communities in thermally fluctuating environments (14:30-14:55)

Ami Taitelbaum – Population Dynamics in a Changing Environment: The effect of the noise properties (14:55-15:20)

Oliver Meacock – Three sides of the same coin: Unifying context-dependencies of ecological interactions (15:40-16:05)

Ohad Vilk – Non-Markovian zero-sum rock-paper-scissors game (16:05-16:30)

Short talks, Thursday 11th July:

Victor Maull – A synthetic microbial Daisyworld: planetary regulation in the test tube (16:30-16:45)

Paras Jain – Cell-state transitions and density-dependent interactions together explain the dynamics of spontaneous epithelial-mesenchymal heterogeneity in cancer cells (16:45-17:00)

Keynote talk, Friday 12th July:

Florence Bansept – Host-associated microbial communities: stories of migration (09:00-10:00)

What is the role of microbial migration in the establishment and maintenance of host-associated microbial communities?  In addition to being widely spread in nature, bi-phasic life cycles – in which microbes spend part of their time in a host, part of their time in the environment – are thought to represent a first step towards host association. We aim at understanding what selection pressures apply to microbes following such a life style. By combining mathematical modeling and experimental evolution, we uncover the contribution of migration to microbial fitness. In particular, we derive predictions that are consistent with experimental observations of an increased ability to form biofilms in bacteria evolved in biphasic conditions with C. elegans. Feeding is an important source of microbial migration for the gut microbiome. In community ecology, immigration is considered a key factor to maintain the diversity of a local community; furthermore, a diverse gut microbiome is usually considered an important determinant of health. Thus, questions arise: do hosts adapt their feeding behavior so as to manipulate microbial immigration in a way that facilitates the maintenance of a diverse flora? What fluctuations are to be expected in the community composition from feeding intermittence, and should sampling be controlled for it? We develop mathematical models of microbial communities with birth, death and intermittent migration to study these questions. So far, we have shown that intermediate feeding frequencies facilitate coexistence in a multi-species community, and that a food more concentrated in microbes relaxes the constraint around the optimal feeding frequency. We will compare our theoretical results with experimental studies in different animals, as we expect this effect to depend on host characteristics, like typical carrying capacity or transit time.

Contributed talks, Friday 12th July:

Julian Lee – Inference of Causal Interaction Network of Gut Microbiota (10:00-10:25)

Xiaotong Zhang – Can pairwise cocultures predict complex microbiome dynamics? (10:25-10:50)

Short talks, Friday 12th July:

George Constable – Maternal transmission as a microbial symbiont sieve and the absence of lactation in male mammals (11:20-11:45)

Roberto Corral López – Deciphering Dysbiosis: Modeling the Ecological Dynamics of the Gut Microbiome (11:45-12:00)