Sask. study shows tiny doses of certain pesticides hurt flying insects

A new study from the University of Saskatchewan says even trace amounts of a widely-used pesticide make it difficult for flying insects to detect dangerous situations.

And that could have implications for bee populations.

The U of S experiments involved locusts, but the researchers involved believe the results apply to other flying insects.

The locusts were treated with trace amounts of neonicotinoid pesticides. Even residual doses made it difficult for the insects to spot predators and objects in their path.

Neonicotinoids are used on crops to prevent losses to pests and other insects while the crops are in the early stages of development.

"Even though the insect seemed to be just fine, it survived, it was walking around, it could fly, and all those sorts of things, it seemed to lack the ability to avoid something coming at it," said Jack Gray, researcher and an expert in neural control of animal behaviour at the U of S. 

"So, from a behavioural perspective, that's very important for the animal's survival."

When researchers used higher doses of the chemical, the locusts weren't able to fly straight or didn't take off at all.

Neonic pesticides are widely used across the country, especially in canola production, In 2012, the chemical was used over 11 million hectares of crops across the prairies, or roughly 44 per cent of the region's crop land.

Last year, Health Canada proposed banning two neonicotinoid pesticides and phase them out over the next three to five years. Numerous studies have linked neonics to declining insect populations, including bees.

The research team was surprised to find the insects were affected even after their bodies had metabolized or broken down the chemicals.

The study used a specially-designed wind tunnel to test the locust's ability to fly around simulated objects.

Researchers also found the insects' motion-detector neurons were less sensitive after being treated, as well as their ability to process and respond to objects quickly while flying. 

"The nervous system that processes visual processes, it seemed like it was severely impaired," said Gray.

"It wasn't able to detect the kinds of motion that would normally trigger some kid of avoidance response."

The paper, which was published in the journal Neuro Toxicology, is part of a wider study at the university on how trace amounts of the pesticides can affect flying insects.

Researchers at the U of S plan to turn their attention to bees in future studies.