Data to: Carotenoids-based reddish pelvic spines in non-reproducing female and male sticklebacks (Gasterosteus aculeatus) – signalling social dominance?

Conspicuous ornaments are often considered a result of evolution by sexual selection. According to the social selection hypothesis, such conspicuous traits may also evolve as badges of status associated with increased boldness or aggression towards conspecifics in conflicts about ecological resources. This study tested predictions from the social selection hypothesis to explain evolution of conspicuous red colour of the pelvic spines of the three-spine stickleback (Gasterosteus aculeatus). Wild non-reproducing sticklebacks were presented to pairs of dummies which differed at their pelvic spines, having either (i) normal sized grey or red pelvic spines, or (ii) normal sized grey or large red pelvic spines. The experimental tank was illuminated by white or green light, since green light impedes the sticklebacks’ ability to detect red colour. The dummies moved slowly around in circles at each end of the experimental tank. We quantified the parameters (i) which of the two dummies was visite...