title: Role of the iridescent eye in stickleback female mate choice.
abstract: Many vertebrates exhibit prominent body colours that are used in courtship and territorial communication. Some fishes also have an eye whose iris becomes iridescent during the mating season, as in the threespine stickleback. Behavioural studies in this species have focused on the redness of the throat/jaw as the primary determinant of female mate choice. Unlike the iridescent eye, however, the red throat/jaw is not present in all stickleback populations, suggesting that the colour of the eye may be equally important for female mate choice. Here, we used data on photoreceptors and environmental light to assess body conspicuousness and the colour contrast of courtship signals for stickleback populations living in a range of waters, from clear (mesotrophic) to red light shifted (dystrophic). This analysis indicated that the redness of the throat/jaw is expressed to enhance the contrast of the eye. To test the importance of eye colour as a courtship signal, we carried out mate choice experiments in which females were presented with identical videos of a courting male but for the colour of the eye and/or the throat/jaw. Females did not choose based on differences in throat/jaw redness between videos, but preferred males with the highest contrast between the eye and the throat/jaw. This result points to the blue iridescent eye as a primary courtship signal in stickleback female mate choice.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada V3J 4M5. inigo@sfu.ca
authors.forename: Iñigo Novales
authors.initials: IN
authors.lastname: Flamarique
authors.forename: Carolyn
authors.initials: C
authors.lastname: Bergstrom
authors.forename: Christiana L
authors.initials: CL
authors.lastname: Cheng
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Reimchen
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology*; D015350:Contrast Sensitivity; D005123:Eye / Q000033:anatomy & histology*; D005260:Female; D008297:Male; D052586:Mating Preference, Animal / Q000502:physiology*; D055620:Optical Phenomena; D010858:Pigmentation / Q000502:physiology*; D023701:Smegmamorpha / Q000502:physiology*; D014741:Video Recording
keywords: behaviour; body reflection; colour contrast; nuptial signal; sexual selection