Well-lit cities keeping bees awake and ruining their love life, claims study

Bee
Bee

Light pollution is making bees sleep-deprived and harming their mating waggle dance, a study has found.

Artificial light from vehicles, street lights, road signs and other sources are seeping into the natural world and increasingly disrupting the lives of insects and also animals.

A study of honey bees has found that exposure to light around the clock disrupts the internal body clock of the insects and causes them to sleep less.

Sleep deprivation has been linked to a worsening of the waggle dance which is essential to how the bees find a mate and breed.

The waggle dance is also an intricate communication system between the bees which informs hive mates about the location of food sources.

Lit up bees can't sleep
Long exposure to light ‘significantly disrupted’ the circadian rhythms of honey bees and their behaviour, said researchers - School of Biological Sciences, UC San Diego/ SWNS

Researchers at the University of California, San Diego, compared groups of bees that enjoyed 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 behaviour.

As the bees were videoed 24 hours a day during the experiments, study lead author Ashley Kim, a PhD candidate, said the impact was immediately obvious.

“Even without analysing the data, you can tell that there was something going on. The bees that were under constant light slept less,” she said.

“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.”

Prof James Nieh and graduate student Ashley Kim at the University of California, San Diego
‘You can tell that there was something going on,’ said Ashley Kim, pictured with fellow study author Prof James Nieh at the University of California, San Diego - School of Biological Sciences, UC San Diego/ SWNS

She added that there are “significant concerns” about the health of the bees, but also what knock-on implications this may have on the wider environment because bees play such a key role as a pollinator.

Honey bees usually prefer to nest in dark environments, although a small amount of light can enter through the hive entrance.

While the prevalence of light pollution varies from region to region, urban environments are increasingly exposed to artificial light conditions.

The research team say bees are now more exposed to light pollution as a result of urban sprawl and also due to a surge in the popularity of beekeeping in urban areas.

The research showed that bees exposed to continuous light slept less and were more frequently disturbed by other bees compared to those kept in normal darkness.

Bees under continuous light also showed a preference for darker areas within their experimental cages.

Bright lights
Light pollution in America has led to researchers fearing honey bees are being sleep-deprived – and the same may apply to the UK - School of Biological Sciences, UC San Diego/ SWNS

Prof James Nieh, study co-author, added: “Understanding the factors that affect bee health, such as light pollution, is essential for developing strategies to protect pollinator populations.

“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.”

A 2022 report from the House of Lords states that biodiversity loss (along with climate change) is among the “biggest medium to long term risks to UK domestic food production”.

A report on the impact of light pollution by the London Assembly said: “It is essential for our survival to understand and address the different contributing factors to biodiversity loss, and light pollution is part of that picture.”

The US study is published in the journal Scientific Reports.