Biology subjects

Chemtob, Y.

Publications and source records attributed to Chemtob, Y..

3 recordsLinked to original sources

bioRxiv2026

Zebrafish shoals share leadership during continuous decision-making on the move in a three-room Y-maze

Collective decision-making in animal groups is often studied using short, trial-based mazes experimental setups that restrict observations to isolated choice events. However, how leadership and decision dynamics unfold over extended periods in symmetric environments remains poorly understood. Here we introduce a novel cyclic three-room Y-shaped environment that enables continuous, and autonomous sequences of collective decisions without experimental reset. We tracked the positions and identities of 20 groups of five AB-strand zebrafish (Danio rerio) during one-hour sessions in which animals freely transitioned between three identical rooms connected by visually isolated identical corridors. We show that this symmetric Y-maze enables the collection of large amounts of data to study decision-making with a few replicates, because habituation occurs after 45 minutes of exploration. After an initial exploration phase, groups reached a stable behavioural regime, generating thousands of decision events per replicate. Collective dynamics were consistent across spatial contexts, indicating that the symmetric architecture does not bias movement patterns, as opposed to traditional mazes. We show that zebrafish leadership is typically shared among shoal members, with leaders often acting as decision-makers. By transforming a classical maze into a self-renewing decision system, this approach enables the study of long-term collective dynamics and spontaneous leadership in controlled yet ecologically relevant conditions. Author summarypresentation

animal behavior and cognition↗

bioRxiv2019

Strategies to modulate zebrafish collective dynamics with a closed-loop biomimetic robotic system

The objective of this study is to integrate biomimetic robots into small groups of zebrafish and to modulate their collective behaviours. A possible approach is to have the robots behave like sheepdogs. In this case, the robots would behave like a different species than the fish and would present different relevant behaviours. In this study, we explore different strategies that use biomimetic zebrafish behaviours. In past work, we have shown that robots biomimicking zebrafish can be socially integrated into zebrafish groups. We have also shown that a fish-like robot can modulate the rotation choice of zebrafish groups in a circular set-up. Here, we further study the modulation capabilities of such robots in a more complex set-up. To do this, we exploit zebrafish social behaviours we identified in previous studies. We first modulate collective departure by replicating the leadership mechanisms with the robot in a set-up composed of two rooms connected by a corridor. Then, we test different behavioural strategies to drive the fish groups towards a predefined target room. To drive the biohybrid groups towards a predefined choice, they have to adopt some specific fish-like behaviours. The first strategy is based on a single robot using the initiation behaviour. In this case, the robot keeps trying to initiate a group transition towards the target room. The second strategy is based on two robots, one initiating and one staying in the target room as a social attractant. The third strategy is based on a single robot behaving like a zebrafish but staying in the target room as a social attractant. The fourth strategy uses two robots behaving like zebrafish but staying in the target room. We conclude that robots can modulate zebrafish group behaviour by adopting strategies based on existing fish behaviours. Under these conditions, robots enable the testing of hypotheses about the behaviours of fish.

animal behavior and cognition↗

bioRxiv2018

Loose social organisation of AB strain zebrafish groups in a two-patch environment

We study the collective behaviour of zebrafish shoals of different numbers of individuals (1, 2, 3, 5, 7, 10 and 20 AB zebrafish Danio rerio) in a constraint environment composed of two identical square rooms connected by a corridor. This simple set-up is similar to a natural patchy environment. We track the positions and the identities of the fish and compute the metrics at the group and at the individual levels. First, we show that the number of fish affects the behaviour of each individual in a group, the cohesion of the groups, the preferential interactions and the transition dynamics between the two rooms. Second, during collective departures, we show that the rankings of exit correspond to the topological organisations of the fish prior to their collective departure. This spatial organisation appears in the group a few seconds before a collective departure. These results provide new evidences on the spatial organisation of the groups and the effect of the number of fish on individual and collective behaviours in a patchy environment.

animal behavior and cognition↗