Artificial Light Is Disrupting Bees’ Sleep - The Secret To Waking Up Refreshed

Summary: A study by researchers at UC San Diego reveals that artificial light disrupts the circadian rhythms of honey bees, reducing their sleep and impairing behaviors crucial for their role as pollinators. The findings highlight the potential threat of light pollution to bee health and, consequently, to the ecosystems and food security that rely on their pollination services.

Key Takeaways:

Artificial Light Reduces Bee Sleep: Prolonged exposure to artificial light significantly disrupts the sleep patterns of honey bees, leading to decreased rest and increased disturbances among hive members.
Impact on Bee Communication: Poor sleep affects bees’ ability to perform their “waggle dance,” a vital behavior used to communicate the location of food sources, which could impair the overall efficiency of the colony.
Rising Concern of Light Pollution: As urban beekeeping grows and climate change increases nighttime temperatures, bees may face greater exposure to light pollution, potentially threatening their health and pollination services.

In an emerging red flag for the digital era, sleep experts have warned us to avoid screen time in bed, sounding the alarm that light emitted from phones and other electronic devices can disrupt our sleep patterns. That’s one way that science is waking up to the broad range of health and disease implications related to circadian biology and our daily sleep-wake cycles.

Now, researchers at the University of California San Diego have found that light disruption is not only a health concern for humans. A new study led by PhD candidate Ashley Kim and Professor James Nieh, PhD, in the School of Biological Sciences has found that artificial light disrupts the circadian rhythms of honey bees and poses a threat to their essential role as pollinators.

“Our research shows just how sensitive honey bees are to changes in their environment, particularly to something as seemingly benign as artificial light,” says Kim of the study, published in Scientific Reports, in a release. “By disrupting their circadian rhythms, we see clear evidence of reduced sleep periods. This raises significant concerns, not only for bee health but also for the health of ecosystems that depend on them for pollination.”

The Role of Bees in Ecosystems

Honey bees play a crucial role as pollinators of wild plants and important crops, providing services that support ecosystem stability and global food security. Without pollination, crops worth tens of millions of dollars would be at risk.

Honey bees generally prefer to nest in dark environments, although a small amount of light can enter from the hive entrance. Sleeping bees typically remain immobile but exhibit subtle movements if disturbed by nestmates. However, bees sleep outside when they swarm or when they form “bee beards” outside the nest on hot evenings, which are increasing under climate change.

While the prevalence of artificial light at night (ALAN), or light pollution, on sleeping honey bees varies from region to region, modern urban environments are increasingly exposed to artificial light conditions, especially as temperatures rise. Because there has been a resurgence of urban beekeeping in many areas to support bees and their critical pollination services, bees that experience hotter weather are now potentially more exposed to ALAN.

Experiments Reveal Effects on Sleep and Behavior

Like us, when bees experience a poor night’s sleep and disrupted circadian patterns, problems in behavior and function emerge. Sleep is crucial for the health and fitness of honey bee colonies since they depend on an intricate system of communication known as the “waggle dance” that informs hive mates about the location of food sources in the environment. Bees dance more poorly and therefore do not communicate as well if they do not get enough sleep.

Through a series of experiments spanning several years, the UC San Diego researchers compared groups of bees that underwent normal sleep in the dark with others that were subjected to continuous artificial light. The results clearly showed that prolonged exposure to light significantly disrupted the circadian rhythms of honey bees, leading to impaired behaviors. Since the bees were video recorded 24 hours a day during the experiments, Kim could immediately see the effects of disrupted sleep.

“Even without analyzing the data you can tell that there was something going on…the bees that were under constant light slept less,” says Kim in a release. “The effects of light pollution on biological systems is fairly unknown and something people normally don’t think about, which is why it’s a rapidly evolving field.”

Protecting Pollinators from Light Pollution

Among the details described in the paper: Bees exposed to continuous light slept less and were more frequently disturbed by their peers compared to those kept in normal darkness. Also, bees under continuous light exhibited a preference for darker areas within their experimental cages.

“Understanding the factors that affect bee health, such as light pollution, is essential for developing strategies to protect pollinator populations,” says Nieh in a release. “Light pollution is a growing issue, with artificial light now covering a quarter of the Earth’s surface, and this research sheds new light on how such disturbances may be harming pollinators.”