title: Stressful colours: corticosterone concentrations in a free-living songbird vary with the spectral composition of experimental illumination.
abstract: Organisms have evolved under natural daily light/dark cycles for millions of years. These cycles have been disturbed as night-time darkness is increasingly replaced by artificial illumination. Investigating the physiological consequences of free-living organisms in artificially lit environments is crucial to determine whether nocturnal lighting disrupts circadian rhythms, changes behaviour, reduces fitness and ultimately affects population numbers. We make use of a unique, large-scale network of replicated field sites which were experimentally illuminated at night using lampposts emanating either red, green, white or no light to test effect on stress hormone concentrations (corticosterone) in a songbird, the great tit (Parus major). Adults nesting in white-light transects had higher corticosterone concentrations than in the other treatments. We also found a significant interaction between distance to the closest lamppost and treatment type: individuals in red light had higher corticosterone levels when they nested closer to the lamppost than individuals nesting farther away, a decline not observed in the green or dark treatment. Individuals with high corticosterone levels had fewer fledglings, irrespective of treatment. These results show that artificial light can induce changes in individual hormonal phenotype. As these effects vary considerably with light spectrum, it opens the possibility to mitigate these effects by selecting street lighting of specific spectra.
authors: Department of Animal Ecology, The Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands j.ouyang@nioo.knaw.nl.
authors: Jenny Q
authors: JQ
authors: Ouyang
authors: Department of Animal Ecology, The Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
authors: Maaike
authors: M
authors: de Jong
authors: Department of Biology, Max Planck Institute for Ornithology, Evolutionary Physiology Group, Seewiesen, Germany University of Konstanz, Konstanz, Germany.
authors: Michaela
authors: M
authors: Hau
authors: Department of Animal Ecology, The Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
authors: Marcel E
authors: ME
authors: Visser
authors: Nature Conservation and Plant Ecology Group, Wageningen University, Wageningen, The Netherlands.
authors: Roy H A
authors: RH
authors: van Grunsven
authors: Department of Animal Ecology, The Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
authors: Kamiel
authors: K
authors: Spoelstra
mesh_terms: D000818:Animals; D003345:Corticosterone / Q000097:blood*; D003624:Darkness; D008027:Light / Q000009:adverse effects*; D008029:Lighting / Q000009:adverse effects*; D046109:Passeriformes / Q000502:physiology*; D012098:Reproduction / Q000528:radiation effects; D013312:Stress, Physiological
chemical_list: D003345:Corticosterone
keywords: Parus major; artificial light; corticosterone; great tit; light spectra; stress