Bumblebees and flies lose sleep when they are drugged by insecticides

Common pesticides keep some of the most important pollinators from getting a good night’s sleep, according to a new study from the University of Bristol. The research shows that bees and flies exposed to neonicotinoid insecticides, which are commonly used worldwide, are struggling with their sleep and memory.

As a result of their findings, the researchers are urging policymakers in the UK to protect a ban on neonicotinoid insecticides.

A team of scientists led by Dr. Kiah Tasman in Bristol’s School of Physiology, Pharmacology and Neuroscience conducted two studies to investigate the effects of neonicotinoids on bumblebees and fruit flies. The substances were found to prevent sleep, which may help explain why many insect pollinators are vanishing.

“The neonicotinoids we tested had a big effect on the amount of sleep taken by both flies and bees. If an insect was exposed to a similar amount as it might experience on a farm where the pesticide had been applied, it slept less, and its daily behavioral rhythms were knocked out of sync with the normal 24-hour cycle of day and night,” said Dr. Tasman.

In the first study, the researchers examined the neurological effects of the pesticides in the brains of fruit flies. 

The investigation revealed that typical agricultural concentrations of neonicotinoids completely disrupted the flies’ ability to remember. The substances also changed the circadian clock in the fly brain that controls sleep-wake cycles.

“Being able to tell time is important for knowing when to be awake and forage, and it looked like these drugged insects were unable to sleep. We know quality sleep is important for insects, just as it is for humans, for their health and forming lasting memories,” explained study senior author Dr. James Hodge.

“Bees and flies have similar structures in their brains, and this suggests one reason why these drugs are so bad for bees is they stop the bees from sleeping properly and then being able to learn where food is in their environment,” said study co-author Dr. Sean Rands.

“Neonicotinoids are currently banned in the EU, and we hope that this continues in the UK as we leave EU legislation.”

The study is published in the journal Scientific Reports.

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By Chrissy Sexton, Earth.com Staff Writer