From disorder to order in marching locusts.
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 the prediction of a rapid transition from disordered to ordered movement and identified a critical density for the onset of coordinated marching in locust nymphs. We also demonstrated a dynamic instability in motion at densities typical of locusts in the field, in which groups can switch direction without external perturbation, potentially facilitating the rapid transfer of directional information.
Buhl
C
C
Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK. camille.buhl@adelaide.edu.au
Sumpter
D J T
DJ
Couzin
I D
ID
Hale
J J
JJ
Despland
E
E
Miller
E R
ER
Simpson
S J
SJ
D000818:Animals; D006110:Grasshoppers / Q000502:physiology*; D008399:Mass Behavior; D008954:Models, Biological; D009068:Movement; D011156:Population Density