Bacterial foraging in patchy landscapes

Individual foraging behavior of Escherichia coli via chemotaxis and the emergence of traveling population waves are well understood. How these processes translate to the formation of biofilms and, more generally, the spatial distribution of (meta-) populations in patchy microbial environments remains unclear. To address this question, we fabricated microfluidic devices with 4 parallel arrays of 85 patches connected by corridors where the difference between arrays was the within-landscape corridor width variance (disorder). Using these crystal-like landscapes we followed the spatiotemporal colonization dynamics of E. coli and recorded single cell trajectories (~10⁶) over 24 hours. Interpreting trajectories using the ideal chain model of polymer physics allowed us to decipher the diversity of foraging behaviors in response to the topology of the habitat and local patch/corridor occupancy. Furthermore, we found that higher corridor disorder led to more jamming events and thus aggregation as well as a deviation from the spatial distribution of metapopulations in less disordered landscapes. These results highlight multiscale processes leading to biofilm development and emphasize the role of topology in microbial landscapes for predicting ecological dynamics.