Personality counts: the effect of boldness on shoal choice in three-spined sticklebacks

The grouping behaviour of fish is a widespread phenomenon of high biological significance but little is known as to how consistent individual behavioural differences may affect group joining preferences. When given the option to join either a shy or a bold shoal of three-spined sticklebacks, Gasterosteus aculeatus, both shy and bold individuals showed a strong preference for associating with bold fish. Personality type interacted with individual hunger levels to affect the extent of association, suggesting important strategy variation by focal fish in a competitive foraging environment. Furthermore, shoals modified their behaviour in relation to the focal individual. Individual behavioural differences were shown to have a complex role in influencing association preferences as well as driving previously unrecognized behavioural modifications in foraging groups.