From Disorder to Order in Marching Locusts

  title={From Disorder to Order in Marching Locusts},
  author={J{\'e}r{\^o}me Buhl and David J. T. Sumpter and Iain D. Couzin and Joseph J. Hale and Emma Despland and Esther R. Miller and Stephen J. Simpson},
  pages={1402 - 1406}
Recent models from theoretical physics have predicted that mass-migrating animal groups may share group-level properties, irrespective of the type of animals in the group. One key prediction is that as the density of animals in the group increases, a rapid transition occurs from disordered movement of individuals within the group to highly aligned collective motion. Understanding such a transition is crucial to the control of mobile swarming insect pests such as the desert locust. We confirmed… 
Onset of collective motion in locusts is captured by a minimal model.
A minimal model is presented to describe the onset of collective motion seen when a population of locusts are placed in an annular arena, and a quantitative comparison is given, showing time series, stationary distributions, and the mean switching times between states.
Inherent noise can facilitate coherence in collective swarm motion
A coarse-grained approach to the study of directional switching in a self-propelled particle model assuming an underlying one-dimensional Fokker–Planck equation for the mean velocity of the particles is adopted, revealing that individual locusts appear to increase the randomness of their movements in response to a loss of alignment by the group.
Criticality and the onset of ordering in the standard Vicsek model
Recent finite-size scaling and dynamical studies of the SVM are reviewed, which present a full characterization of the continuous phase transition through dynamical and critical exponents, and a complex network analysis of SVM flocks is presented.
Group structure in locust migratory bands
The results indicate that locust band structure and dynamics differ markedly from what is known about other large moving groups such as fish schools or bird flocks, yet they still conform to key general predictions made by collective movement models that explain how billions of individuals can align using local interactions.
Ergodic directional switching in mobile insect groups.
The 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.
Ordering dynamics in collectively swimming Surf Scoters.
Anisotropic Interaction and Motion States of Locusts in a Hopper Band
This work reconstructs nearly twentythousand individual trajectories composed of over 3.3 million locust positions and suggests novel interactions, namely that locusts change their motion to avoid colliding with neighbors in front of them.
New numerical results are shown indicating that the apparent discontinuity of the phase transition may in fact be a numerical artifact produced by the articial periodicity of the boundary conditions.
Fluctuation-Induced Phase Separation in Metric and Topological Models of Collective Motion.
It is shown that fluctuations induce a density-dependent shift of the onset of order, which in turn changes the nature of the transition into a phase-separation scenario.


Spontaneously ordered motion of self-propelled particles
We study a biologically inspired, inherently non-equilibrium model consisting of self-propelled particles. In the model, particles move on a plane with a velocity of constant magnitude; they locally
Onset of collective and cohesive motion.
It is found that this phase transition, in two space dimensions, is always discontinuous, including for the minimal model of Vicsek et al. for which a nontrivial critical point was previously advocated.
Spatial scales of desert locust gregarization.
Computer simulations and a laboratory experiment are presented that show how differences in resource distributions, conspicuous only at small spatial scales, can have significant effects on phase change at the population level; local spatial concentration of resource induces gregarization.
The Dynamics of Herds: From Individuals to Aggregations
Abstract The dynamic behavior of small herds is investigated by means of simulations of two-dimensional discrete-stochastic models. An individual-based approach is used to relate collective behavior
Intermittency and clustering in a system of self-driven particles.
The study of the cluster statistics shows that both the cluster sizes and the transition probability between them follow power-law distributions and the exchange of particles between clusters is shown to satisfy detailed balance.
Collective memory and spatial sorting in animal groups.
The first evidence for collective memory is presented in such animal groups (where the previous history of group structure influences the collective behaviour exhibited as individual interactions change) during the transition of a group from one type of collective behaviour to another.
Novel type of phase transition in a system of self-driven particles.
Numerical evidence is presented that this model results in a kinetic phase transition from no transport to finite net transport through spontaneous symmetry breaking of the rotational symmetry.