PESTICIDE RESEARCH
PH.D student Sinan Zhang prepares a locust for a test. Zhang works with Professor Jack Gray, whose research on how pesticides — including supposedly safer chemicals — affect locusts has implications for many other species, including bumblebees.
University of Saskatchewan researchers blasted locusts with pesticides, attached electrodes to their neurons and threw them into a computer simulation, and the results could hold important clues for the health of bee populations.
Professor Jack Gray says his lab’s recent study found locusts that were exposed to a non-lethal dose of a pesticide in the neonicotinoid family became disoriented when met with a simulated oncoming object.
“We can make inferences on how this will impact other species like bumblebees,” Gray said.
The findings are the result of a novel combination of research techniques.
Former PHD student Rachel Parkinson, the paper’s lead author, embedded electrodes into the thoraxes of African migratory locusts and put them into a computer simulator. The goal was to measure how the insects responded to oncoming objects by measuring the electrical signals from their nervous system.
They sprayed locusts with small doses of two pesticides and compared their nervous system activity to a control group.
When used at the right dose, the two pesticides are about equally lethal. But the experiment showed that non-lethal doses of the neonicotinoid caused the signals from the confused bugs to become weaker, indicating they were disoriented.
“They can still see,” Gray explained. “But they can’t detect motion.”
Since part of the nervous system is common across many species, it’s possible the same thing could happen to other insects exposed to a non-lethal dose, like bees.
That could prevent worker bees from collecting nectar or even cause them to leave their colony, which could cause the collapse of bee populations, which are already threatened.
Gray cautioned that more research is needed to confirm whether the other pesticide used in the experiment is a safer option. He also stressed that the research shouldn’t be interpreted as a call to cease the use of pesticides.
But he said there could be cause for concern in light of locust swarms that have blanketed East Africa in recent months. The locusts, which are about the size of a human thumb, travel in swarms of millions and can consume their body weight in crops. Farmers in countries like Kenya have responded by “dumping ” pesticides on fields, Gray said, which he worries could have adverse environmental impacts.
“Based on videos I’ve seen … those farmers are just absolutely blasting the swarms with pesticides,” Gray said.
Neonicotinoids are a controversial type of pesticide.
Their development suggested they were safer than other chemicals, but recent findings indicate they’ve had a dire effect on bee populations. They’ve been banned in the European Union and within the city limits of some cities, including Montreal.
Gray said future research from Parkinson, who is now pursuing post-doctoral studies at the University of Oxford, will look at how bumblebees are affected by the chemical.
“It’s a bit too new. We don’t know exactly what (neonicotinoids) do,” Gray said.