VIDEO PLAYBACK EXPERIMENTS ON STICKLEBACK MATE CHOICE - FEMALE MOTIVATION AND ATTENTIVENESS TO MALE COLOR CUES

When female three-spined sticklebacks, Gasterosteus aculeatus, were presented simultaneously two video playbacks of a courting male, one playback displayed in colour and the other in greytone, the female approached and attempted to follow both displays. Females that responded strongly to playback of the male clearly preferred the coloured display, whereas those that responded less showed no consistent preference for coloured or greytoned displays. Females showed some approach to playback of a non-reproductive female but did not prefer the coloured over the greytoned one. These results suggest that the female's sexual motivation influences the,mechanism(s) mediating her attraction to nuptially coloured males. Although highly motivated animals may typically show reduced selectivity in successive choice situations, they appeared to be more selective in the simultaneous choice situation studied here, perhaps because they attend more to male nuptial coloration, or because they become less fearful of brightly coloured males. These results demonstrate the effectiveness of video playback for investigating the role of visual cues in stickleback behaviour. They also emphasize the value of considering motivational factors in studies on sexual selection and, especially, when designing or interpreting experiments on mate choice.