Boldness and social interactions in three-spined stickleback (Gasterosteus aculeatus)

• Main Author: Harcourt, J. L.
• Published: University of Cambridge 2011
• Subjects: 591.5
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603678

Animals that forage in groups often shown high levels of synchrony in their behaviour, yet the issue of individuality versus collective response has been, until recently, a poorly studied topic. In this thesis, I sue three-spined stickleback (<i>Gasterosteus aculeatus) </i>to address the issue of coordinated foraging with respect to individual level variability. I explore the impact that differing levels of boldness (a well studied and consistent behavioural trait) have on shoal choice, pace-setting, leadership and information use. I start in chapter two by investigating how boldness affects group joining preferences. There is a clear preference for associating with bold shoals and hunger state affects the extent to which this is seen. I also find behavioural modification by the shoals, adding further complexity to group dynamics. In chapter three I identify a mechanism underlying joint foraging trips in mis-matched pairs. This experiment illustrates that bolder individuals show greater initiative but that less bold fish provide positive social feedback which elicits greater leadership in their partners. I continue in chapter four to explore conflict in foraging pairs and find a mechanism by which alternation can be monitored and maintained. Finally, in chapter five, I discuss information use and identify different responses to observing others depending on boldness. Together, this work gives insight into social foraging in small groups and highlights the importance of individual behavioural characteristics.