Meeting Abstract
Light pollution, or the presence of unnatural light at night, is a widespread yet understudied anthropogenic stressor. Although impacts of light pollution on wildlife have become apparent over the years, the mechanisms by which artificial light at night affects their physiology and behavior are not well understood. For example, avian reservoir species exposed to dim light at night exhibit decreased resistance to West Nile virus. The hormone melatonin (i.e. the “chemical expression of darkness”) is secreted in darkness and suppressed in the presence of light. This indolamine coordinates daily rhythms within the body including metabolism and immune functions. Because melatonin plays such an integral role in coordinating these physiological functions, it remains a possibility that light pollution induced suppression of melatonin leads to maladies in wildlife. To investigate whether melatonin is suppressed by dim light at night, we exposed wild-caught house sparrows (Passer domesticus) to ~6 lux light at night in captivity for 3 weeks and measured melatonin at 5 points throughout the night. This study emphasizes that light pollution can influence hormonal regulation and potentially mediate downstream circadian incoordination or physiological functions that lead to detrimental outcomes in wildlife.
