BPCPPDYSOE21 – scientific programme

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BP: Fachverband Biologische Physik

BP 9: Systems Biology II

BP 9.1: Invited Talk

Monday, March 22, 2021, 14:00–14:30, BPc

From individual to collective intermittent motion: from bacteria to sheep — •Fernando Peruani — CY Cergy Paris University, Cergy, France

Intermittent behavior is observed in biological systems at all scales, from bacterial systems to sheep herds. First, I will discuss how Escherichia coli explores surfaces by alternating stop and moving phases. Specifically, I will show that a stochastic three behavioral state model is consistent with the empirical data. The model reveals that the stop frequency of bacteria is tuned at the optimal value that maximizes the diffusion coefficient. These results provide a new perspective on how evolution may have reshaped the bacterial motility apparatus. Intermittent motion is also observed in Merino sheep, where again a stochastic three behavioral state model provides a quantitative understanding of the empirical data. However, in sheep, individual transition rates depend on the behavioral state of other individuals and collective behaviors emerge. Specifically, I will show that small sheep herds display highly synchronized intermittent collective motion, with the herd behaving as a self-excitable system. Based on the analysis of these two biological systems (bacteria and sheep), we will discuss the need of three behavioral states to describe intermittent motion in biological systems, providing a unified picture of such behavior across scales.

Refs.: Perez Ipina et al. Nature Physics 15, 610-615 (2019); Gascuel et al. Animal behavior (2021); Gomez Nava et al. (2021)