The mechanisms of colour-based mate choice in female threespine sticklebacks: Hue, contrast and configurational, cues

We investigated the importance of male nuptial colouration as a cue for female mate choice in the threespine stickleback Gasterosteus aculeatus L. In courtship preference tests, sexually receptive females were presented with pairs of dummies that differed in the hue, extent or distribution of colouration. Females preferred to court i) a red-bellied dummy over a green-bellied dummy, a uniformly tan dummy, and an all-red dummy and ii) a yellow-bellied dummy over a red-bellied dummy. Females showed no preferences when presented with i) an all-red and uniformly tan dummy and ii) two dummies that differed only in the location of red colouration (belly versus dorsum). In the three experiments in which females preferred a 25% red dummy, the proportion of courtship directed to this dummy increased with overall female responsiveness. The results of mathematical models of colour opponent and luminosity processing suggest that female preferences are influenced by a male's belly colour contrast and not by merely its brightness contrast.