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Author Yadav, G.; Malik, S.; Rani, S.; Kumar, V.
Title Role of light wavelengths in synchronization of circadian physiology in songbirds Type Journal Article
Year 2014 Publication Physiology & Behavior Abbreviated Journal Physiol Behav
Volume (down) Issue Pages
Keywords Activity; Animals; Bunting; Cortisol; Light wavelength; Melatonin; Weaver bird
Abstract This study investigated whether at identical duration and equal energy level birds presented with short (450nm; blue, B) and long (640nm; red, R) light wavelengths would differentially interpret them and exhibit wavelength-dependent circadian behavioral and physiological responses, despite the difference in their breeding latitudes. Temperate migratory blackheaded buntings (Emberiza melanocephala) and subtropical non-migratory Indian weaverbirds (Ploceus philippinus) initially entrained to 12h light:12h darkness (12L:12D; L=0.33muM/m2/s, D=0muM/m2/s) in two groups of each, groups 1 and 2, were subjected to constant light (LL, 0.33muM/m2/s), which rendered them arrhythmic in the activity behavior. They were then exposed for about two weeks each to 12B:12R and 12R:12B (group 1) or 12R:12B and 12B:12R (group 2) at 0.33muM/m2/s light energy level. Blue and red light periods were interpreted as the day and night, respectively, with activity and no-activity in non-migratory weaverbirds or activity and intense activity (Zugunruhe, migratory night restlessness) in the migratory buntings. Consistent with this, plasma melatonin levels under B:R, not R:B, light cycle were low and high in blue and red light periods, respectively. A similar diurnal pattern was absent in the cortisol levels, however. These results show an important role of light wavelengths in synchronization of the circadian clock governed behavior and physiology to the photoperiodic environment, and suggest that photoperiodic timing might be a conserved physiological adaptation in many more birds, regardless of the difference in breeding latitudes, than has been generally envisaged.
Address DST-IRHPA Centre for Excellence in Biological Rhythms Research, Department of Zoology, University of Delhi, Delhi 110 007, India. Electronic address: drvkumar11@yahoo.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9384 ISBN Medium
Area Expedition Conference
Notes PMID:25536387 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 1080
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