According to recent research conducted by experts and biologists from the University of Cincinnati, light pollution causes monarch butterflies to lose their way. Monarch butterflies that travel all the way to Canada from Mexico and back during their multigenerational migration can become disoriented due to light pollution. The research was published in the science journal- iScience.

Researchers found that butterflies generally rest or settle down for the night near artificial illumination like a porch light or streetlight. The artificial light interferes with the butterfly’s circadian rhythms causing disorientation the next day. Thus, light pollution causes monarch butterflies to lose their capacity to navigate.

Artificial light impacts butterflies in such a way that it obstructs the molecular processes responsible for the butterfly’s extraordinary navigational ability. It then triggers the butterfly to take flight when it should be resting. According to the University of Cincinnati assistant professor Patrick Guerra, the research even found that the butterflies treat any light source, such as a light at a construction site, as if it is the sun.

It is difficult to imagine that monarch butterflies stick to a fixed plan as they fly around your garden. However, the migration pattern of the monarch butterfly takes it thousand of miles away to the exact forest in Mexico, where they spend the whole winter.

Migration is essential as the behavior of species depends on the environment. That is why researchers now want to know if light pollution is causing monarch butterflies distress while migrating.

According to co-author Samuel Stratton, several migrants travel through urban areas. Data on these migrations would help examine the impacts of light pollution on orientation and migratory outcomes. Monarch butterflies depend on the dark (night) to process proteins vital to their inner compass. This aids the butterfly in navigating its way to the southern wintering ground. As monarchs and other species keep track of day and night through molecular systems, light pollution can obstruct their circadian rhythms and sleep-wake cycles.

Several monarch butterflies in the east of the Rocky Mountains leave their summer breeding grounds in the northern United States and southern Canada to travel 4,000 kilometers to overwintering sites in Mexico. Monarchs take up to five generations to travel to Mexico and back. While traveling, they use their internal compass to orient themselves to the changing positing of the sun.

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However, monarchs exposed to artificial illumination can go through a phase shift, making their bodies think it is earlier or later than it is. Researchers found that light pollution makes the monarchs feel that the day is long.

Experts suggest that porch lights and other unnecessary lights should be switched off to avoid obstructing monarchs and other species’ migratory patterns.