Randomness in the choice of neighbours promotes cohesion in mobile animal groups

Jadhav, V and Guttal, V and Masila, DR (2022) Randomness in the choice of neighbours promotes cohesion in mobile animal groups. In: Royal Society Open Science, 9 (3).

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Abstract

Classic computational models of collective motion suggest that simple local averaging rules can promote many observed group-level patterns. Recent studies, however, suggest that rules simpler than local averaging may be at play in real organisms; for example, fish stochastically align towards only one randomly chosen neighbour and yet the schools are highly polarized. Here, we ask - how do organisms maintain group cohesion? Using a spatially explicit model, inspired from empirical investigations, we show that group cohesion can be achieved in finite groups even when organisms randomly choose only one neighbour to interact with. Cohesion is maintained even in the absence of local averaging that requires interactions with many neighbours. Furthermore, we show that choosing a neighbour randomly is a better way to achieve cohesion than interacting with just its closest neighbour. To understand how cohesion emerges from these random pairwise interactions, we turn to a graph-theoretic analysis of the underlying dynamic interaction networks. We find that randomness in choosing a neighbour gives rise to well-connected networks that essentially cause the groups to stay cohesive. We compare our findings with the canonical averaging models (analogous to the Vicsek model). In summary, we argue that randomness in the choice of interacting neighbours plays a crucial role in achieving cohesion. © 2022 Royal Society Publishing. All rights reserved.

Item Type:	Journal Article
Publication:	Royal Society Open Science
Publisher:	Royal Society Publishing
Additional Information:	The copyright for this article belongs to Royal Society Publishing
Department/Centre:	Division of Biological Sciences > Centre for Ecological Sciences Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	18 May 2022 06:20
Last Modified:	18 May 2022 06:20
URI:	https://eprints.iisc.ac.in/id/eprint/71815

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