Emergent oscillations in dense adaptive cell populations

Dynamical quorum sensing is one of the simplest group behaviours in cell populations, where collective oscillations emerge via mutual signaling when cells reach beyond a critical density. While some examples have been extensively studied, their biological function remains confounding, sug- gesting a non-functional origin of collective oscillations. Here, by considering the response of cells to the extracellular signal and vice versa, we develop a quantitative theory for the phenomenon, and present a necessary condition for collective oscillations in a communicating population. We further show that a sufficient condition for oscillations is fulfilled by cells with adaptive signaling systems, which are ubiquitous in biology. These general results were elucidated from non-equilibrium thermodynamic principles, where stimulated energy release from active cells drives oscillations in the medium. The unexpected link between adaptation and oscillation is shown to underlie several known examples of dynamical quorum sensing, and as such may also be a source of inadvertent group behaviour in large populations of living organisms.