Random sequential addition simulations of animal aggregations provide null models of group structure

Apparent structure in animal aggregations such as fish and Antarctic krill schools may result from
the tight packing of these elongated animals. This geometrical structure may be difficult to
differentiate from behavior-induced structure resulting from individuals preferentially taking up
certain positions relative to conspecifics to gain an adaptive advantage such as reduced locomotive
cost. Here we use random sequential addition (RSA) simulations to quantify the effect of animal
shape, aggregation organization, and aggregation density on 2D school structure. This technique
allows for the generation of a null model for nearest neighbor distance and nearest neighbor
position angle for a specific body shape and aggregation density, thus isolating the effect of
geometry from that of behavior. We further identify a shape-specific aggregation density threshold
above which the animal shape affects the spatial distribution of nearest neighbors. Nearest neighbor
distance data of fish s...

Source: Bioinspiration and Biomimetics - April 6, 2019 Category: Science Authors: Daniel Olsen and David W Murphy Source Type: research