Ecology and multilevel selection explain aggression in spider colonies.
Progress in sociobiology continues to be hindered by abstract debates over methodology and the relative importance of within-group vs. between-group selection. We need concrete biological examples to ground discussions in empirical data. Recent work argued that the levels of aggression in social spider colonies are explained by group-level adaptation. Here, we examine this conclusion using models that incorporate ecological detail while remaining consistent with kin- and multilevel selection frameworks. We show that although levels of aggression are driven, in part, by between-group selection, incorporating universal within-group competition provides a striking fit to the data that is inconsistent with pure group-level adaptation. Instead, our analyses suggest that aggression is favoured primarily as a selfish strategy to compete for resources, despite causing lower group foraging efficiency or higher risk of group extinction. We argue that sociobiology will benefit from a pluralistic approach and stronger links between ecologically informed models and data.
Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, UK OX1 3RB, UK.
Jay M
JM
Biernaskie
Department of Zoology, University of Oxford, South Parks Road, Oxford, UK OX1 3PS, UK.
Kevin R
KR
Foster
D000222:Adaptation, Physiological; D000374:Aggression; D000818:Animals; D017753:Ecosystem; D008954:Models, Biological; D012641:Selection, Genetic; D012919:Social Behavior; D013112:Spiders / Q000235:genetics* / Q000502:physiology*
AIC; Adaptation; Anelosimus studiosus; animal personality; competition; group selection; inclusive fitness; information theoretic; kin selection; model-based inference