Collective predator evasion: Putting the criticality hypothesis to the test

According to the criticality hypothesis , collective biological systems should operate in a special parameter region, close so-called critical points, where behavior undergoes qualitative change between different dynamical regimes. Critical exhibit unique properties, which may benefit information processing such as maximal responsiveness external stimuli. Besides neuronal and gene-regulatory networks, recent empirical data suggests that also animal collectives be examples of self-organized systems. However, open questions about self-organization mechanisms groups remain: Evolutionary adaptation towards group-level optimum (group-level selection), implicitly assumed “criticality hypothesis”, appears general not reasonable for fission-fusion composed non-related individuals. Furthermore, previous theoretical work relies on non-spatial models, ignore potentially important spatial sorting effects. Using generic, spatially-explicit model schooling prey being attacked by predator, we show first schools operating at perform best. this is due optimal response suggested but rather structure school criticality. Secondly, investigating individual-level evolution, strong self-sorting effects point lead selection gradients, make it an evolutionary unstable state. Our results demonstrate decisive role spatio-temporal phenomena behavior, viable mechanism self-tuning unrelated