- Open Access
Nonlinear Competition Avoidance Favors Coexistence in Spatially Structured Microbial Populations
PRX Life 4, 043011 – Published 5 November, 2026
DOI: https://doi.org/10.1103/4t9n-nvgc
Abstract
Bacteria regulate their motility through a variety of mechanisms, including quorum sensing and other density-dependent responses mediated by diffusible signals. While nonlinear density-dependent motility is well known in active-matter theory to generate nonequilibrium spatial patterns, its consequences for the coexistence of growing, interacting species remain less explored. Here we develop a minimal spatially structured model for two strongly competing species in which local demographic interactions are coupled to an escape response: Each species increases its motility nonlinearly (sigmoidal) with the local abundance of its competitor. We show that this sigmoidal motility regulation promotes optimal spatial self-organization and can sustain long term coexistence via segregation, even in parameter regimes that yield competitive exclusion in well-mixed Lotka-Volterra dynamics. On two-dimensional lattices, the interplay between demographic competition and density-dependent motility generates a range of emergent patterns, including regimes in which the weaker competitor counterintuitively has higher total abundance. Overall, our results identify nonlinear, competitor-induced motility as a fundamental mechanism capable of sustaining coexistence in competing microbial populations.
Physics Subject Headings (PhySH)
Article Text
Supplemental Material
References (48)
- N. Wadhwa and H. Berg, Bacterial motility: Machinery and mechanisms, Nat. Rev. Microbiol. 20, 161 (2022).
- E. Budrene and H. Berg, Complex patterns formed by motile cells of Escherichia coli, Nature (London) 349, 630 (1991).
- C. M. Waters and B. L. Bassler, Quorum sensing: Cell-to-cell communication in bacteria, Annu. Rev. Cell Dev. Biol. 21, 319 (2005).
- R. Daniels, J. Vanderleyden, and J. Michiels, Quorum sensing and swarming migration in bacteria, FEMS Microbiol. Rev. 28, 261 (2004).
- H. H. Hoang, N. Gurich, and J. E. González, Regulation of motility by the expr/sin quorum-sensing system in Sinorhizobium meliloti, J. Bacteriol. 190, 861 (2008).
- R. F. Kinsinger, M. C. Shirk, and R. Fall, Rapid surface motility in Bacillus subtilis is dependent on extracellular surfactin and potassium ion, J. Bacteriol. 185, 5627 (2003).
- G. Cárcamo-Oyarce, P. Lumjiaktase, R. Kümmerli, and L. Eberl, Quorum sensing triggers the stochastic escape of individual cells from Pseudomonas putida biofilms, Nat. Commun. 6, 5945 (2015).
- R. Daniels, S. Reynaert, H. Hoekstra, C. Verreth, J. Janssens, K. Braeken, M. Fauvart, S. Beullens, C. Heusdens, I. Lambrichts, D. E. De Vos, J. Vanderleyden, J. Vermant, and J. Michiels, Quorum signal molecules as biosurfactants affecting swarming in Rhizobium etli, Proc. Natl. Acad. Sci. USA 103, 14965 (2006).
- J. Tailleur and M. E. Cates, Statistical mechanics of interacting run-and-tumble bacteria, Phys. Rev. Lett. 100, 218103 (2008).
- M. E. Cates and J. Tailleur, Motility-induced phase separation, Annu. Rev. Condens. Matter Phys. 6, 219 (2015).
- A. I. Curatolo, N. Zhou, Y. Zhao, C. Liu, A. Daerr, J. Tailleur, and J. Huang, Cooperative pattern formation in multi-component bacterial systems through reciprocal motility regulation, Nat. Phys. 16, 1152 (2020).
- A. Dinelli, J. O'Byrne, A. Curatolo, Y. Zhao, P. Sollich, and J. Tailleur, Non-reciprocity across scales in active mixtures, Nat. Commun. 14, 7035 (2023).
- Y. Duan, J. Agudo-Canalejo, R. Golestanian, and B. Mahault, Dynamical pattern formation without self-attraction in quorum-sensing active matter: The interplay between nonreciprocity and motility, Phys. Rev. Lett. 131, 148301 (2023).
- W. J. M. Ridgway, M. P. Dalwadi, P. Pearce, and S. J. Chapman, Motility-induced phase separation mediated by bacterial quorum sensing, Phys. Rev. Lett. 131, 228302 (2023).
- A. Dinelli, A. Altieri, and J. Tailleur, Random motility regulation drives the fragmentation of microbial ecosystems, Phys. Rev. E 114 014404 (2026).
- M. Mattei, D. Soriano-Paños, M. Halappanavar, and A. Arenas, Structured interactions drive abrupt transitions in the spatial organization of microbial communities, Phys. Rev. Res. 7, 043210 (2025).
- O. Hallatschek, S. S. Datta, K. Drescher, J. Dunkel, J. Elgeti, B. Waclaw, and N. S. Wingreen, Proliferating active matter, Nat. Rev. Phys. 5, 407 (2023).
- K. Z. Coyte, J. Schluter, and K. R. Foster, The ecology of the microbiome: Networks, competition, and stability, Science 350, 663 (2015).
- P. Chesson, Mechanisms of maintenance of species diversity, Annu. Rev. Ecol. Syst. 31, 343 (2000).
- P. Amarasekare, Competitive coexistence in spatially structured environments: A synthesis, Ecol. Lett. 6, 1109 (2003).
- B. M. Bolker and S. W. Pacala, Spatial moment equations for plant competition: Understanding spatial strategies and the advantages of short dispersal, Am. Nat. 153, 575 (1999).
- T. K. Fuller and L. B. Keith, Non-overlapping ranges of coyotes and wolves in northeastern Alberta, J. Mammal. 62, 403 (1981).
- H. Webster, J. W. McNutt, and K. McComb, African wild dogs as a fugitive species: Playback experiments investigate how wild dogs respond to their major competitors, Ethology 118, 147 (2012).
- S. M. Durant, Living with the enemy: Avoidance of hyenas and lions by cheetahs in the Serengeti, Behav. Ecol. 11, 624 (2000).
- M. E. Cates, D. Marenduzzo, I. Pagonabarraga, and J. Tailleur, Arrested phase separation in reproducing bacteria creates a generic route to pattern formation, Proc. Natl. Acad. Sci. USA 107, 11715 (2010).
- M. Mattei and A. Arenas, Exploring spatial segregation induced by competition avoidance as driving mechanism for emergent coexistence in microbial communities, Phys. Rev. E 110, 014404 (2024).
- See Supplemental Material at http://link.aps.org/supplemental/10.1103/4t9n-nvgc for additional analyses including heterogeneous initial conditions, alternative neighborhood structures, a different motility function, and variations of the model parameters (), (), (), and ().
- L. R. Thompson, J. G. Sanders, D. McDonald, A. Amir, J. Ladau, K. J. Locey, R. J. Prill, A. Tripathi, S. M. Gibbons, G. Ackermann, J. A. Navas-Molina, S. Janssen, E. Kopylova, Y. Vázquez-Baeza, A. González, J. T. Morton, S. Mirarab, Z. Zech Xu, L. Jiang, M. F. Haroon, et al., A communal catalogue reveals earth's multiscale microbial diversity, Nature (London) 551, 457 (2017).
- T. H. M. P. Consortium, Structure, function and diversity of the healthy human microbiome, Nature (London) 486, 207 (2012).
- R. M. May, Will a large complex system be stable? Nature (London) 238, 413 (1972).
- J. Grilli, Macroecological laws describe variation and diversity in microbial communities, Nat. Commun. 11, 4743 (2020).
- J. Camacho-Mateu, A. Lampo, M. Sireci, M. A. Muñoz, and J. A. Cuesta, Sparse species interactions reproduce abundance correlation patterns in microbial communities, Proc. Natl. Acad. Sci. USA 121, e2309575121 (2024).
- O. X. Cordero and M. S. Datta, Microbial interactions and community assembly at microscales, Curr. Opin. Microbiol. 31, 227 (2016).
- S. L. O'Brien, S. M. Gibbons, S. M. Owens, J. Hampton-Marcell, E. R. Johnston, J. D. Jastrow, J. A. Gilbert, F. Meyer, and D. A. Antonopoulos, Spatial scale drives patterns in soil bacterial diversity, Environ. Microbiol. 18, 2039 (2016).
- R. U. Sheth, M. Li, W. Jiang, P. A. Sims, K. W. Leong, and H. H. Wang, Spatial metagenomic characterization of microbial biogeography in the gut, Nat Biotechnol 37, 877 (2019).
- K. J. Welch, A. Liebman-Peláez, and E. I. Corwin, Biogeography of a human oral microbiome at the micron scale, Proc. Natl. Acad. Sci. USA 113, 10807 (2016).
- S. A. Levin, Dispersion and population interactions, Am. Nat. 108, 207 (1974).
- N. Shigesada, K. Kawasaki, and E. Teramoto, Spatial segregation of interacting species, J. Theor. Biol. 79, 83 (1979).
- M. Mimura and K. Kawasaki, Spatial segregation in competitive interaction-diffusion equations, J. Math. Biol. 9, 49 (1980).
- L. Stone and A. Roberts, The checkerboard score and species distributions, Oecologia 85, 74 (1990).
- T. Dallas, B. A. Melbourne, and A. Hastings, When can competition and dispersal lead to checkerboard distributions? J. Anim. Ecol. 88, 269 (2019).
- J. M. Diamond, Assembly of species communities, in Ecology and Evolution of Communities, edited by M. L. Cody and J. M. Diamond (Harvard University Press, Cambridge, MA, 1975), pp. 342–444.
- E. F. Connor and D. Simberloff, The assembly of species communities: Chance or competition? Ecology 60, 1132 (1979).
- S. Gude, E. Pinçe, K. M. Taute, A.-B. Seinen, T. S. Shimizu, and S. J. Tans, Bacterial coexistence driven by motility and spatial competition, Nature (London) 578, 588 (2020).
- D. Gravel, F. Massol, and M. Leibold, Stability and complexity in model meta-ecosystems, Nat. Commun. 7, 12457 (2016).
- J. Denk and O. Hallatschek, Self-consistent dispersal puts tight constraints on the spatiotemporal organization of species-rich metacommunities, Proc. Natl. Acad. Sci. USA 119, e2200390119 (2022).
- G. Garcia Lorenzana, A. Altieri, and G. Biroli, Interactions and migration rescuing ecological diversity, PRX Life 2, 013014 (2024).
- NIST digital library of mathematical functions, https://dlmf.nist.gov/8.17.