Light at night, clocks and health: from humans to wild organisms.

The increasing use of electric lights has modified the natural light environment dramatically, posing novel challenges to both humans and wildlife. Indeed, several biomedical studies have linked artificial light at night to the disruption of circadian rhythms, with important consequences for human health, such as the increasing occurrence of metabolic syndromes, cancer and reduced immunity. In wild animals, light pollution is associated with changes in circadian behaviour, reproduction and predator-prey interactions, but we know little about the underlying physiological mechanisms and whether wild species suffer the same health problems as humans. In order to fill this gap, we advocate the need for integrating ecological studies in the field, with chronobiological approaches to identify and characterize pathways that may link temporal disruption caused by light at night and potential health and fitness consequences.