Effect of artificial light at night on sleep and metabolism in weaver birds
Artificial light at night is constantly minimizing the span of dark nights from the natural light-dark cycle of earth. Over the past century, the lightscape of earth has completely changed owing to technological advancements which subsequently changed the lifestyle of human as well as the nearby animal species. This motivated the present study, wherein we investigated the impact of light at night (LAN) on behavior and physiology of a diurnal passerine finch, baya weaver (Ploceus philippinus). A group of bird (N=10) exposed to 12L:12D photoperiod was initially subjected to dark nights (0 lux) for a period of 10 days followed by 5 lux; night light for a span of 4 weeks. First week in LAN served as acute treatment with respect to fourth week (chronic). Acute exposure had more pronounced impact on the behavioral and physiological observations when compared with chronic treatment. The results reveal significant increase in nighttime activity, sleep loss, significant inclusion of drowsiness behavior during the day in response to LAN. Beside these behavioral alterations, changes in physiological parameters such as; reduction in body mass, loss of gradient between pre- and post-prandial blood glucose levels, elevation in plasma corticosterone levels were more prominent during acute exposure of LAN. Plasma metabolites such as triglycerides, total protein, serum glutamic-oxaloacetic transaminase (SGOT) and creatinine concentrations also hiked in response to LAN treatment. Thus, the study broadly enumerates the impact of acute and chronic exposure of LAN on behavior (rest/sleep) and physiology (metabolism) of birds.