dual effect of stickleback nuptial coloration on rivals manipulation of a graded signal using video playback
Adult males of the marine form of Gasterosteus aculeatus (stickleback) displayed agonistic behavior towards red undersides of rival males. ... An adult male stickleback was previously recorded for two minutes in the tank. The video was later simultaneously ran through both monitors next to the tank with only one stickleback occupying the test tank. Only the intensities of the nuptial coloring was altered in each trial. ... The stickleback was also placed facing forward so it could see both monitors when they were turned on.