The Evolution of Communication Mechanisms in Self-Organised Ecological Aggregations: Impact on Pattern Formation

Collective behaviours in animal communities are the result of inter-individual communication. However, communication signals are not fixed; they evolve to ensure more effective interactions between the emitter and receiver of these signals. In this study we use a mathematical approach and investigate the effect of changes in communication signals (at both receiver and emitter levels) on the aggregation patterns displayed by these animal communities. We use simple linear stability analysis to study the impact that the loss/gain in signals strength has on the formation of stationary and moving animal aggregations. We then use numerical simulations to study the impact of these signal strengths on the long-term persistence of some stationary and moving aggregations. We show that a reduction in the strength of such communication signals can stop the movement of some aggregations. Moreover, for very weak signals, one can obtain a variety of standing wave patterns characterised by left-moving and right-moving waves of individuals passing through each other, with or without some individuals joining the opposite-moving group.