Download Full Text (9.2 MB)
Artificial light at night (ALAN) is a human-caused phenomenon that is disrupting the daily cycles of animals. Circadian disruption via ALAN, even at low levels, can disrupt development, behavior, and physiological function, including altered melatonin levels, increased secretion of glucocorticoids, decreasing body mass, and disrupting patterns of rest and arousal. However, in some cases, immunocompetency has increased in response to ALAN. The response to stress caused by ALAN may alter the energy budget of animals. We hypothesized that two demanding physiological responses, immunocompetency and telomere elongation, may compete for limited resources in developing birds. We tested this by exposing house sparrow (Passer domesticus) and tree swallow (Tachycineta bicolor) chicks to ALAN at a level of approximately 1 lux in nest boxes for five nights pre-fledging. We conducted E. coli bacterial killing assays on plasma and measured telomere lengths from DNA collected before and after exposure. As the nestlings aged immunocompetency increased, but we found no effects of ALAN exposure. Surprisingly, telomere lengths increased in response to ALAN in house sparrows. We will discuss the effects of ALAN on physiological trade-offs and compare outcomes between a declining native and successful invasive species.
Dr. Elizabeth Danka, Biology and Dr. Stephen Ferguson, Biology
biology, artificial light at night, ALAN
Fimreite, Morgan and Williams, Harrison, "Physiological effects of artificial light at night on two cavity-nesting passerines" (2023). Student Presentations. 98.