Just about every creature has to sleep, and sleep patterns respond to light and darkness. One of those creatures is the honey bee, whose nests are within the reach of outdoor lighting.
"In the cases of my paper, I show one instance where on our campus there was a honey bee colony that was building their nest, mostly likely due to swarming,” said behavioral ecologist Ashley Kim, a doctoral student at UC San Diego.
"This nest was very close to a street lamp, so when I was documenting and taking pictures of this nest, we knew they were getting exposure to this light."
Kim and her research team did a study where they kept bees constantly exposed to light that was calibrated to be the same intensity of common street lamps. Their paper was published in Scientific Reports.
Kim said the artificial light had an effect on the bees' internal clocks.
"Over time, throughout our trial, we found around days four and five they started to lose their internal clock rhythm. And that was when they were like, 'I don’t know when to sleep.' And so they were taking more naps throughout the day," Kim said.
Overall, they slept significantly less. Previous studies show their foraging would be impaired. Bees use an activity called a waggle dance to show other bees the way to food. And with little sleep the dance is affected and their directions can be inaccurate.
An excess of artificial light also disrupts the circadian rhythms of humans. Disrupted sleep patterns through excessive artificial light or shift work is just plain bad for your health.
"If you have severe circadian disruptions, pretty much every chronic disease is associated with it," said Emily Manoogian, a staff scientist at the Salk Institute.
"You’re going to have an increased risk for diabetes, cardiovascular events. Affective disorders like bipolar, depression, reflux, irritable bowel syndrome. Almost anything you can think of."
Manoogian said every living organism has circadian rhythms. They were originally observed in plants.
The bees, studied by Kim, were European honey bees, which sleep in their hives at night. They suffer greater exposure to light when they swarm or sleep outside in the summer.
"It’s basically too hot inside of their colony so bees will naturally hang outside of the nest, just to cool down,” Kim said.
She added that artificial light will affect some of the agricultural and ecological functions of bees, reducing their ability to forage and to pollinate plants.
