Ergodic directional switching in mobile insect groups

TL;DR

This paper models collective locust movement using a Fokker-Planck equation, revealing complex noise-driven behaviors and suggesting that directional switches are due to intrinsic ergodic effects in group formation.

Contribution

It introduces a novel Fokker-Planck framework for locust swarm dynamics, highlighting the role of internal noise and ergodic effects in collective directional switching.

Findings

Stationary distribution exhibits non-monotonic transition indicators.

Behavior arises naturally from system randomness, challenging standard noise transition theories.

Group direction switches are due to inherent ergodic effects, not external stimuli.

Abstract

We obtain a Fokker-Planck equation describing experimental data on the collective motion of locusts. The noise is of internal origin and due to the discrete character and finite number of constituents of the swarm. The stationary probability distribution shows a rich phenomenology including non-monotonic behavior of several order/disorder transition indicators in noise intensity. This complex behavior arises naturally as a result of the randomness in the system. Its counterintuitive character challenges standard interpretations of noise induced transitions and calls for an extension of this theory in order to capture the behavior of certain classes of biologically motivated models. Our results suggest that the collective switches of the group's direction of motion might be due to a random ergodic effect and, as such, they are inherent to group formation.