But two new studies have shown that a common pesticide disrupts the sleep of bees and flies – with major consequences for the important insects.
In one study, researchers looked at the effect of pesticides on bumblebees’ behavior by feeding the creatures nectar sugar laced with neonicotinoids – one of the most commonly used pesticides – and then tracking their movements in a foraging arena.
The impact of the pesticide – comparable to the amount a bee would encounter in the wild – was huge.
“It seems to disrupt the body clock when bumblebees forage – they forage a lot less, more of that foraging happens at night, and they sleep a lot more during the day. It causes a misconception of their normal behavior,” Kiah Tasman, teacher at the University of Bristol’s School of Physiology, Pharmacology and Neuroscience, told CNN.
This, she explained, could have serious consequences: “It’s quite alarming because other studies and our studies show that motivation for foraging has decreased.”
Many plants – including the fruits and vegetables we eat and feed to our livestock – depend on pollinators, such as bees, to reproduce.
According to the World Wildlife Fund, nearly 90% of the world’s wild plants and 75% of the world’s major crops depend on animal pollination.
Bees take on much of this workload: Pollinators, mostly honey bees, are responsible for one mouth in three of food we take, according to the United States Department of Agriculture, and are increasing crop values in the U.S. by more than $ 15 billion a year.
But bees and other pollinators are threatened by the widespread use of pesticides, habitat loss, the climate crisis and parasites, so much so that the odds of spotting the hardworking bumblebee in Europe and America have been more than 30% since the last century. decreased.
Tasman warned that bees are now “rather sluggish and yet go out less often.”
“If the time they manage to go out and forage is at night when there are no flowers available, that will greatly reduce how successful they are in gathering the food the colony needs to grow and settle down. to reproduce, ”said Tasman, lead author. of the studies, said.
In a second study, published Thursday, the researchers focused their attention on flies – again, by exposing them to neonicotinoids and then using infrared rays to track how this affected movement.
The results showed that the pesticide acts directly on the cells in the brain that control the body’s clock, which decide when sleep and activity occur during the day – and confuse them.
“It seems that these pesticides freeze these cells during the day, so the body doesn’t know if it’s day or night,” said Tasman, adding that it’s very likely that the same kind of mechanism that happens in the flies is happening. in bees.
Researchers say their studies can help us better understand how these pesticides affect vulnerable insects.
“It also gives us hints as to what we could research if we made more pest-specific pesticides – if we understand exactly how they work in the insects, we might be able to make one that only works on pests,” added Tasman.