Collective detection based on visual information in animal groups

We investigate key principles underlying individual, and collective, visual detection of stimuli, and how this relates to the internal structure of groups. While the individual and collective detection principles are generally applicable, we employ a model experimental system of schooling golden shiner fish (Notemigonus crysoleucas) to relate theory directly to empirical data, using computational reconstruction of the visual fields of all individuals. This reveals how the external visual information available to each group member depends on the number of individuals in the group, the position within the group, and the location of the external visually detectable stimulus. We find that in small groups, individuals have detection capability in nearly all directions, while in large groups, occlusion by neighbours causes detection capability to vary with position within the group. To understand the principles that drive detection in groups, we formulate a simple, and generally applicable, model that captures how visual detection properties emerge due to geometric scaling of the space occupied by the group and occlusion caused by neighbours. We employ these insights to discuss principles that extend beyond our specific system, such as how collective detection depends on individual body shape, and the size and structure of the group.

Automated summary

Our study focuses on the key principles underlying individual and collective detection of stimuli, particularly in relation to the internal structure of groups. By using a model experimental system of schooling fish, we were able to directly relate theoretical findings to empirical data and uncover how external visual information available to group members varies based on group size, position within the group, and location of visually detectable stimuli. We discovered that in small groups, individuals have detection capability in all directions, while in large groups, occlusions by neighbors cause detection capability to vary with position within the group. Additionally, a simple and generally applicable model was formulated to explain how visual detection properties emerge from geometric scaling of group space and occlusion caused by neighbors.