Insect insomnia: Common pesticide keeping bees, flies up at night

BRISTOL, England — The sleep needs of insects probably isn’t a topic most people ponder on a daily basis, but just like the rest of us, insects and bugs need adequate shuteye to function properly. Now, an interesting new study from the University of Bristol finds that the most frequently used pesticide in the world is interfering with the sleep of both bees and flies.

Researchers theorize that the detrimental impact of neonicotinoid insecticides on the sleep habits of bees and flies may partially explain why so many pollinator populations are declining all over the world.

“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 synch with the normal 24-hour cycle of day and night,” says lead study author Dr. Kiah Tasman, Teaching Associate in the School of Physiology, Pharmacology and Neuroscience, in a release.

After examining the impact of this pesticide on insect brains, researchers also report that exposed bees and flies have “ruined” memories. Sleep is very important to proper memory formation among humans, and the same is likely true for these insects. They’re not sleeping, so they’re also not remembering.

“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,” adds senior study author Dr. James Hodge, Associate Professor in Neuroscience in the School of Physiology, Pharmacology and Neuroscience.

“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,” concludes study co-author Dr. Sean Rands, Senior Lecturer in the School of Biological Sciences. “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 Scientific Reports.