Fluctuating environments drive insect swarms into a new state that is robust to perturbations

Rothamsted Research - Harpenden, Hertfordshire, AL5 2JQ, UK

^(a) andy.reynolds@rothamsted.ac.uk

Received: 20 July 2018
Accepted: 7 November 2018

Abstract

In contrast with laboratory insect swarms, wild insect swarms display significant coordinated behaviour. Here it is hypothesised that the presence of a fluctuating environment drives the formation of transient, local order (synchronized subgroups), and that this local order pushes the swarm as a whole into a new state that is robust to environmental perturbations. The hypothesis finds support in a theoretical analysis and in an analysis of pre-existing telemetry data for swarming mosquitoes. I suggest that local order is sufficient to make swarms fault-tolerant and that the swarm state and structure may be tuneable with environmental noise as a control parameter. The new theory opens a window onto thermodynamic descriptions of swarm behaviours and extends a long-standing analogy with self-gravitating systems.