Artificial light acting on bird brains similarly to a pollutant
In a recent study published in the Proceedings of the Royal Society B, researchers have found that long-term exposure to artificial light at night (ALAN) significantly impacts the social behavior, brain function, and circadian rhythms of zebra finches.
The research, which lasted for three weeks, involved 104 zebra finches, with half kept in individual cages and the other half in group cages containing six birds (three males and three females). The birds were subjected to 12 hours of light followed by 12 hours of darkness, with ALAN at night, while the isolated birds continued with the same light and darkness cycle.
The study aimed to understand how ALAN affects the social interactions of zebra finches and how this impacts their behavior. The findings suggest that social interactions significantly amplify circadian disruptions caused by ALAN.
ALAN negatively impacts social interactions in zebra finches, with disruptions to interaction patterns due to altered light conditions affecting group dynamics and individual biological rhythms. Birds in grouped cages exposed to ALAN had more disrupted natural rhythms in their brain and livers compared to the isolated birds who were also exposed to ALAN.
Exposure to ALAN acts like a pollutant to the brain of social birds such as zebra finches, altering neurological processes that are crucial for social behavior and other brain functions. ALAN also disrupts the natural circadian rhythms of zebra finches, which normally synchronize to day-night cycles through environmental cues like sunlight.
The social environment plays a significant role in shaping circadian rhythms and the biological responses to ALAN. Group-housed finches show more dramatic effects on rhythms and behavior under ALAN exposure compared to solitary birds, suggesting social interactions normally help regulate their biological timing but become a vulnerability factor under light pollution.
Despite some mortality during the experiment, the researchers noted that this did not significantly influence the observed behavioral and physiological patterns. The authors also propose that future research should investigate the long-term effects of social conditions and ALAN, as long-term exposure might result in social buffering or habituation effects.
The authors of the study highlight that social interactions play a significant role in shaping individual and group biological rhythms, but are often overlooked in the context of environmental stressors like ALAN. These findings have implications for conservation efforts mitigating ALAN's effects on wild bird populations.
The study focused on the zebra finch (Taeniopygia guttata), a small bird found across Australia and islands of Indonesia. Half of the isolated birds were subjected to conditions mimicking ALAN - 12 hours of light (675 lux) followed by 12 hours of dimmed light (about 5 lux). Birds exposed to ALAN were significantly more active at night.
Artificial light at night is a growing concern for disrupting the natural physiological and behavioral rhythms of many animals. The findings from this study underscore the importance of considering social dynamics in studies of light pollution's ecological impacts.
Science has shown that artificial light at night (ALAN) can significantly impact the social behavior and circadian rhythms of zebra finches, a species widely studied in the field of biology. Furthermore, the research suggests that technology like ALAN not only disrupts the natural circadian rhythms of these birds but also affects their social interactions, which play a vital role in shaping individual and group biological rhythms.
