Local interaction rules and collective motion in black neon tetra (Hyphessobrycon herbertaxelrodi) and zebrafish (Danio rerio).

Abstract

We explored the local motion rules used by interacting individuals in small groups of black neon tetra (Hyphessobrycon herbertaxelrodi) and zebrafish (Danio rerio) to ascertain if and how these rules underlie the fishes' global collective coordinated motion. As these 2 species show very different styles of collective motion in terms of cohesion and polarization, we expected to find differences in their individual behavioral rules. We recorded groups of 2, 3, 4, and 8 fish of each species; tracked their individual trajectories; and studied how their individual turning angles and accelerations varied as a function of heading differences, distances, and relative angles to their neighbors. We found that black neon tetra and zebrafish differed in terms of their preferential positions with respect to their neighbors, the magnitude of turning angles and accelerations, and the way these angles and accelerations are modulated by both the distance from neighbors (thus suggesting a "repulsion" zone in black neon tetra but not in zebrafish) and the heading difference and relative angle to neighbors. Our results enable us to infer that, in black neon tetra, avoiding excessive proximity and collision takes priority over cohesion, and cohesion takes priority over polarization. This provides evidence that rules are similar in species of very different genera and that differences are a matter of degree. Our results also provide substantial empirical evidence to support the theoretical assumptions made in agent-based models that simulate coordinated collective motion in many different animal species.

A data-driven method for reconstructing and modelling social interactions in moving animal groups

“…as a function of pairs of other quantities (relative position, velocity or orientation, angle of perception of other individuals, etc.). These quantities only make sense in a framework of the physical world described by a mathematical model which, even if it is often not mentioned explicitly in studies [18,19,22,23] (but see also [13,24,25]), is usually based on equations of motion built in analogy with Newtonian mechanics. The method essentially consists in defining this framework and deriving the mathematical model describing the relation between the quantities used to quantify the behaviour of an organism and its interactions with other organisms or physical objects that are present in its environment.…”

Motion leadership and local interaction in two species of freshwater fish (Danio rerio and Hyphessobrycon herbertaxelrodi)

“…In addition, data‐driven modelling shows detailed interaction rules in moving groups of fish (Escobedo et al ., 2020; Heras et al ., 2019; Zienkiewicz et al ., 2015; Zienkiewicz et al ., 2018). Moreover, two features (global cohesion and polarization) that characterize collective motion at the macro level can be explained by dyadic interaction rules based on changes in the direction and velocity of the individuals, with the kind of movement at the group level being inferred from the relationships between these variables at the micro level (Quera et al ., 2019).…”

“…Although the universality of the interaction rules from which CCM emerges remains to be explored, results indicate that the rules are similar in the species from three distinct families: (a) Cyprinidae ( Notemigonus crysoleucas and Danio rerio ), (b) Poeciliidae ( Gambusia holbrooki ) and (c) Characidae ( Hyphessobrycon herbertaxelrodi , Hemmigrammus rhodostomus and Pristella maxillaris ). As the results published in the past 15 years show, a set of local interaction rules based on the relative position of the individuals and their accelerations, distances and turning angles, among other measures, underlie CCM ( e.g ., Calovi et al ., 2018; Herbert‐Read et al ., 2011; Katz et al ., 2011; Quera et al ., 2019; Rosenthal et al ., 2015; Schaerf et al ., 2017), with differences between species likely to be quantitative rather than qualitative. Comparative studies have explored the differences in the CCM of different fish species ( e.g ., Leem et al ., 2012; Soria et al ., 2007).…”

“…Comparative studies have explored the differences in the CCM of different fish species (e.g., Leem et al, 2012;Soria et al, 2007). Gimeno et al (2016) and Quera et al (2019) compared zebrafish and black neon tetra and found that although the two species had different styles of CCM (a higher polarization in black neon tetra than in zebrafish), the relationships between acceleration, turning angle, relative angle and the distance from a fish to its neighbours followed similar rules in both species, with the differences between them characterized by different magnitudes of the parameters in the functions related to those variables. Fish schools tend to show a weak dominance hierarchy and are considered egalitarian societies in which any individual can act as a leader at any given moment; leadership is assumed to be temporary and "equipotential" (Breder, 1954;Pavlov & Kasumyan, 2000).…”

A data-driven method for reconstructing and modelling social interactions in moving animal groups

“…explicit and yet concise model, whose agreement with 449 experiment can be tested, and whose predictions can be 450 further investigated experimentally. not mentioned explicitly in studies [17,18,20,21] (but 462 see also [13,22,23]), is usually based on equations of 463 motion built in analogy with Newtonian mechanics. is independent of the model.…”