title: Modulation of environmental light alters reception and production of visual signals in Nile tilapia.
abstract: Signal reception and production form the basis of animal visual communication, and are largely constrained by environmental light. However, the role of environmental light in producing variation in either signal reception or production has not been fully investigated. To chart the effect of environmental light on visual sensitivity and body colouration throughout ontogeny, we measured spectral sensitivity, lens transmission and body pattern reflectance from juvenile and adult Nile tilapia held under two environmental light treatments. Spectral sensitivity in juveniles reared under a broad-spectrum light treatment and a red-shifted light treatment differed mostly at short wavelengths, where the irradiance of the two light treatments differed the most. In contrast, adults held under the same two light treatments did not differ in spectral sensitivity. Lens transmission in both juveniles and adults did not differ significantly between environmental light treatments, indicating that differences in spectral sensitivity of juveniles originated in the retina. Juveniles and adults held under the two environmental light treatments differed in spectral reflectance, and adults transferred to a third, white light treatment differed in spectral reflectance from their counterparts held under the two original treatments. These results demonstrate that environmental light plays a crucial role in shaping signal reception in juveniles and signal production throughout ontogeny, reinforcing the notion that environmental light has the capacity to influence animal communication, and suggesting that the characteristics of environmental light should be considered in models of ecological speciation.
authors.affiliation: Department of Biology, Queen's University, Kingston, ON, Canada. m.hornsby@uleth.ca
authors.forename: Mark A W
authors.initials: MA
authors.lastname: Hornsby
authors.forename: Shai
authors.initials: S
authors.lastname: Sabbah
authors.forename: R Meldrum
authors.initials: RM
authors.lastname: Robertson
authors.forename: Craig W
authors.initials: CW
authors.lastname: Hawryshyn
mesh_terms: D000818:Animals; D001835:Body Weight / Q000528:radiation effects; D023681:Cichlids / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D004777:Environment; D007908:Lens, Crystalline / Q000502:physiology / Q000528:radiation effects; D008027:Light; D055537:Light Signal Transduction / Q000528:radiation effects*; D012168:Retinal Pigments / Q000378:metabolism; D013057:Spectrum Analysis; D014796:Visual Perception / Q000528:radiation effects*
chemical_list: D012168:Retinal Pigments
keywords: animal communication; body colouration; ontogenetic variation; sensory drive; visual sensitivity