Personality in a group living species : social information, collective movements and social decision-making

Abstract

Animals need to make constant decisions throughout their lives and to make optimal decisions individuals rely on information. Information can be obtained in two distinct ways: personal or social information. The current paradigm in the information theory use in animal ecology assumes that the decision between using either personal or social information is entirely flexible and context dependent. However, the potential link between variation in personality and information use has received little attention. In this thesis I studied the effect of personality on the use of personal and social information in barnacle geese. I show that individual barnacle geese differ consistently in boldness and that boldness affects the type of information individuals use in various different contexts: In a maze solving task, a producer scrounger game and a public information experiment I found that bold individuals use less social information compared to shy individuals, providing strong evidence that the type of information individuals prefer to use depends on their boldness level. To study the ultimate causes of variation in boldness and the relationship between boldness and social information use I used an experimental and theoretical approach. In a producer scrounger experiment I tested whether the rare personality type outperformed the common personality type which could lead by means of negative frequency dependent selection to the maintenance of variation in boldness. Parallel to that I used a genetic algorithms approach to study the co-evolution of boldness and foraging tactic use in a producer scrounger game. The experimental results as well as the genetic algorithms provided no evidence for a role of negative frequency dependent selection for the maintenance of variation in boldness. Rather, our simulations suggest that differences in selection pressures in space or time (i.e., fluctuating environments) in a social foraging game may cause variation in boldness levels between populations. In our simulations bold individuals evolved to play both producer and scrounger, whereas shy individuals remained confined to scrounging, suggesting that shy individuals have difficulties when they have to collect personal information and that this might be the explanation for the increased tendency of shy individuals to use social information. I experimentally confirmed these model predictions in an experiment in which I forced individuals in either a producer or a scrounger role. Therefore, I argue that the value of social information is higher for shy individuals as compared to bold individuals since it is more costly for shy individuals to collect personal information. This thesis challenges the current paradigm that the decision between using either personal or social information is entirely context dependent. Rather, I provide evidence that personality affects the trade off between using personal and social information. </p