Andrew J. King ∙ Ella G. Henry ∙ Simon Garnier ∙ William L. Allen ∙ Robert J.P. Heathcote ∙ Marco Fele ∙ Marina Papadopoulou ∙ Daniel W.E. Sankey ∙ Ines Fürtbauer

Trends in Ecology and Evolution

Collective behaviour is widespread in the animal kingdom and can enhance individual
fitness. Yet not all collective behaviours are adaptations. Instead, some may be nonadaptive
or ‘evolutionary spandrels’—traits that originated as by-products in the sense proposed
by Stephen Jay Gould and Richard Lewontin. Here, we argue that self-organising processes
provide a route through which evolutionary spandrels in collective animal behaviour
can occur, and we provide three examples: spatial organisation in primate groups,
division of labour in ants, and insect chorusing. We then consider how such outcomes
may be co-opted into adaptive roles through exaptation and conclude by outlining the
challenges associated with testing adaptive and nonadaptive hypotheses in collective
behaviour research using individual-based studies, phylogenetic comparative analyses,
and agent-based models.

Read the full article at: www.cell.com

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