Early life exposure to artificial light at night affects the physiological condition: An experimental study on the ecophysiology of free-living nestling songbirds

Abstract

Light pollution or artificial light at night (ALAN) is increasingly recognised to be an important anthropogenic environmental pressure on wildlife, affecting animal behaviour and physiology. Early life experiences are extremely important for the development, physiological status and health of organisms, and as such, early exposure to artificial light may have detrimental consequences for organism fitness. We experimentally manipulated the light environment of free-living great tit nestlings (Parus major), an important model species in evolutionary and environmental research. Haptoglobin (Hp) and nitric oxide (NOx), as important indicators of immunity, health, and physiological condition, were quantified in nestlings at baseline (13 days after hatching) and after a two night exposure to ALAN. We found that ALAN increased Hp and decreased NOx. ALAN may increase stress and oxidative stress and reduce melatonin which could subsequently lead to increased Hp and decreased NOx. Haptoglobin is part of the immune response and mounting an immune response is costly in energy and resources and, trade-offs are likely to occur with other energetically demanding tasks, such as survival or reproduction. Acute inhibition of NOx may have a cascading effect as it also affects other physiological aspects and may negatively affect immunocompetence. The consequences of the observed effects on Hp and NOx remain to be examined. Our study provides experimental field evidence that ALAN affects nestlings' physiology during development and early life exposure to ALAN could therefore have long lasting effects throughout adulthood.

Artificial Light at Night Reduces Daily Energy Expenditure in Breeding Great Tits (Parus major)

“…Timing of singing and sleep are also strongly affected by light pollution (Kempenaers et al, 2010;Da Silva et al, 2014;Raap et al, 2015), and such changes are suggested to have physiological consequences (Dominoni et al, 2016). For instance, sleep loss in response to ALAN is associated with reduced body mass and altered concentration of nitric oxide and haptoglobin (Raap et al, 2016b). Such physiological responses to ALAN might differ between urban and rural animals, and suggest the possibility that at least some species might adapt to and thus tolerate the presence of artificial lights.…”

Ambient anthropogenic noise but not light is associated with the ecophysiology of free-living songbird nestlings

“…We did not obtain sufficient amounts of blood from all nestlings in order to perform all analyses, resulting in different sample sizes (fledging mass: 562 nestlings from 85 nests; Hp: 475 nestlings from 78 nests; NOx: 344 nestlings from 58 nests). Sixteen nests from the current study had also been used in a previous experiment as a control group but these were not manipulated (see refs 14 and 15). Nests that were exposed to experimental artificial light inside the nest box during that experiment were excluded from the current study.…”

“…26). Haptoglobin and NOx have also previously been shown to be affected by light at night in an experimental field study 14 . Haptoglobin and NOx may therefore provide useful information on physiological condition, health state and innate immunity 25, 26 .…”

“…Noise exposure alone appears not to affect fledging mass 12 but effects on the immune response have been reported 19 . Developing great tits exposed to artificial light at night had increased Hp and decreased NOx levels 14 and a reduced growth rate 15 . Given that noise and light in songbirds can influence foraging behaviour of parents 27, 28 and sleep behaviour of nestlings 29 , and noise may impair parent offspring communication 30 , we anticipated a negative impact of noise and light on individual health and condition through direct and/or indirect effects.…”

Reducing the environmental footprint of church lighting: matching façade shape and lowering luminance with the EcoSky LED

“…A great deal of recent work in biology has illuminated the unexpected impacts of light on animal physiology (e.g. [1][2][3]), including that of humans [4]. Light has dramatic effects on animal behavior [5][6][7][8], and is in many cases deadly [9][10][11][12].…”