Bacterial chemotaxis without gradient-sensing

TL;DR

This paper proposes a novel model for bacterial chemotaxis where individuals increase motility when hungry, enabling accurate chemotactic behavior without gradient sensing, supported by numerical simulations of traveling bands.

Contribution

It introduces a starvation-driven diffusion model that explains chemotaxis without gradient sensing, aligning with Keller-Segel dynamics.

Findings

Chemotaxis can occur without gradient sensing through hunger-driven motility.

Numerical simulations show traveling band and front solutions.

Starvation-driven diffusion resembles Keller-Segel model dynamics.

Abstract

Models for chemotaxis are based on gradient sensing of individual organisms. The key contribution of Keller and Segel is showing that erratic movements of individuals may result in an accurate chemotaxis phenomenon as a group. In this paper we provide another option to understand chemotactic behavior when individuals do not sense the gradient of chemical concentration by any means. We show that, if individuals increase their motility to find food when they are hungry, an accurate chemotactic behavior may obtained without sensing the gradient. Such a random dispersal has been suggested by Cho and Kim and is called starvation driven diffusion. This model is surprisingly similar to the original derivation of Keller-Segel model. A comprehensive picture of traveling band and front solutions is provided with numerical simulations.