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Initiators, leaders, and recruitment mechanisms in the collective movements of damselfish

Ward, Ashley J. W.; Herbert-Read, James E.; Jordan, Lyndon A.; James, Richard; Krause, Jens; Ma, Qi; Rubenstein, Daniel I.; Sumpter, David J. T.; Morrell, Lesley J.


Ashley J. W. Ward

James E. Herbert-Read

Lyndon A. Jordan

Richard James

Jens Krause

Qi Ma

Daniel I. Rubenstein

David J. T. Sumpter


Explaining how individual behavior and social interac- tions give rise to group-level outcomes and affect issues such as leadership is fundamental to the understanding of collective behavior. Here we examined individual and collective behavioral dynamics in groups of humbug damselfish both before and during a collective movement. During the predeparture phase, group activity increased until the collective movement occurred. Although such movements were precipitated by one individual, the success or failure of any attempt to instigate a collective movement was not solely dependent on this initiator’s behavior but on the behavior of the group as a whole. Specifically, groups were more active and less cohesive before a successful initiation attempt than before a failed attempt. Individ- uals who made the most attempts to initiate a collective movement during each trial were ultimately most likely to lead the collective movement. Leadership was not related to dominance but was con- sistent between trials. The probability of fish recruiting to a group movement initiative was an approximately linear function of the number of fish already recruited. Overall, these results are consistent with nonselective local mimetism, with the decision to leave based on a group’s, rather than any particular individual’s, readiness to leave.


Ward, A. J. W., Herbert-Read, J. E., Jordan, L. A., James, R., Krause, J., Ma, Q., …Morrell, L. J. (2013). Initiators, leaders, and recruitment mechanisms in the collective movements of damselfish. The American naturalist, 181(6), 748-760.

Journal Article Type Article
Acceptance Date Jan 26, 2013
Online Publication Date Apr 12, 2013
Publication Date 2013-06
Journal American Naturalist
Print ISSN 0003-0147
Electronic ISSN 1537-5323
Publisher University of Chicago Press
Peer Reviewed Peer Reviewed
Volume 181
Issue 6
Pages 748-760
Keywords collective decision-making, local interactions, shoaling
Public URL