Social situations increase how light pollution disrupts daily biological rhythms

Social zebra finches exposed to artificial light at night (ALAN) exhibit earlier activity onset and greater disruption in circadian gene expression.

• Social interactions may intensify the effects of ALAN on biological rhythms.
• Zebra finches in social groups under ALAN showed greater disruption in hypothalamic and liver circadian gene expression compared to isolated birds.
• Activity onset in ALAN-exposed birds negatively correlated with hypothalamic gene expression.
• There was a greater disassociation between central and peripheral clock gene expression in social birds exposed to ALAN than in isolated birds.
• Rhythmic melatonin concentrations remained unchanged across treatment groups.

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