Seasonal variation in sleep time: jackdaws sleep when it is dark, but do they really need it?

Autor: van Hasselt SJ; Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands. s.j.van.hasselt@rug.nl., Coscia M; Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands., Allocca G; The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.; School of Biomedical Sciences, The University of Melbourne, Parkville, VIC, Australia.; Somnivore Pty. Ltd., Bacchus Marsh, VIC, Australia., Vyssotski AL; Institute of Neuroinformatics, University of Zurich and Swiss Federal Institute of Technology (ETH), Zurich, Switzerland., Meerlo P; Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands.
Jazyk: angličtina
Zdroj: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology [J Comp Physiol B] 2024 Jun; Vol. 194 (3), pp. 335-345. Date of Electronic Publication: 2023 Oct 03.
DOI: 10.1007/s00360-023-01517-1
Abstrakt: Sleep is an important behavioural and physiological state that is ubiquitous throughout the animal kingdom. Birds are an interesting group to study sleep since they share similar sleep features with mammals. Interestingly, sleep time in birds has been shown to vary greatly amongst seasons. To understand the mechanisms behind these variations in sleep time, we did an electro-encephalogram (EEG) study in eight European jackdaws (Coloeus monedula) in winter and summer under outdoor seminatural conditions. To assess whether the amount and pattern of sleep is determined by the outdoor seasonal state of the animals or directly determined by the indoor light-dark cycle, we individually housed them indoors where we manipulated the light-dark (LD) cycles to mimic long winter nights (8:16 LD) and short summer nights (16:8 LD) within both seasons. Jackdaws showed under seminatural outdoor conditions 5 h less sleep in summer compared to winter. During the indoor conditions, the birds rapidly adjusted their sleep time to the new LD cycle. Although they swiftly increased or decreased their sleep time, sleep intensity did not vary. The results indicate that the strong seasonal differences in sleep time are largely and directly driven by the available dark time, rather than an endogenous annual clock. Importantly, these findings confirm that sleep in birds is not a rigid phenomenon but highly sensitive to environmental factors.
(© 2023. The Author(s).)
Databáze: MEDLINE
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