Exploring the consequences of social responsiveness on leadership using an interactive biomimetic robotic fish

• Applicant: Dr. David Bierbach
• Subject Area: Sensory and Behavioural Biology
• Term: from 2016 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 313498612

Individuals can differ consistently in how they respond to the behavior of their social partners. These differences may well affect interactions of individuals in a group, for example leadership. Leadership comprises two main functional aspects that both could be influenced by individual differences in social responsiveness: (i) a follower may base its decision on which leader to follow on the leaders´s behavior while (ii) a leader´s ability to lead may depend on its responsiveness to the behavior of the follower(s). However, empirical data on individual differences in social responsiveness in a leadership context is rare. It is difficult to measure and manipulate an individual's social responsiveness experimentally. In addition, a systematic manipulation of entire animal groups is often not feasible. One approach to overcome these difficulties is to gain control over individuals´ behavior within a group. For that reason, I will use a newly available interactive biomimetic robotic fish system (Robofish). Robofish is accepted as a conspecific by guppies (Poecilia reticulata) and is able to integrate itself into shoals of live guppies. This is achieved through real-time tracking of both live animals and the Robofish that is then able to adjust its behavior to the live guppies´ actions. With this new tool, I try to answer the following fundamental questions. First, I ask whether guppies differ consistently in their social responsiveness. To answer this question, I will analyze the response of live guppies towards a Robofish that swims on a predefined path through an aquarium. Second, I ask whether an individual´s social responsiveness affects its ability to select among different leaders. I predict that the more socially responsive an individual is, the better it should make adaptive choices between different leaders. To test this prediction, guppies can choose between two simultaneously presented Robofish leaders. One of these two Robofish leaders will have been perceived beforehand as leading to a food source while the other one was not. The more responsive the individual guppy, the more it should follow the leader that was associated with food before. Third, I ask how the social responsiveness of leaders influence their ability to lead groups effectively. Strong leaders express most often their own preferences and, thus, are less socially responsive themselves. Theoretical models predict that those strong leaders are better able to lead larger groups compared to weak but more socially responsive ones. However, splitting events should increase when responsiveness of the leader is below certain thresholds. To test this prediction, I will manipulate interactive Robofish leaders´ social responsiveness and quantify the following behavior of live guppy groups of different size. My approach is new and the proposed experiments could provide empirical data to evaluate several recent theoretical models on collective motion and leadership in animal groups.

• DFG Programme: Research Grants