Some residents who live near Parc Andromède in Gatineau, Que., say they’re at their wits end after being plagued by a proliferation of fiery red insects that “burn” any animal or person that gets in their way.
As their name suggests, European fire ants — also known as Myrmica rubra — are an exotic species in North America, having made their way across the pond in the early 20th century. Their sting is like a painful burn or bee sting.
In a little over a century, they’ve moulded their local environment burgeoning their population in pockets of Quebec and Ontario, shutting out both native plants and animals.
“We were kind of surprised of actually the density of the population,” said Étienne Normandin an entomologist and collection manager at the University of Montreal. He was commissioned by the City of Gatineau to conduct a study of the European red ants in the forested area that backs onto several homes along rue d’Andromède.
They found 78 colonies in and around the park and rue d’Andromède, with an estimated population of� between 90,000 and 300,000 individual insects.
While out examining the area, Normandin and his team experienced the “burn.”
“In a few seconds, I had hundreds of workers of the European fire ants on my legs and they were stinging” he said. “So, I can imagine the residents very close by this green area, they are being [stung].”
One of those residents who now fears gardening in her backyard is Nouzha Idrissi.
Idrissi moved to the neighbourhood last summer and has been plagued by the fire ants ever since.
“Since there are a lot of ants, I cannot enjoy my land,” she she told Radio-Canada in a French interview.
Her husband was once stung so severely his leg got infected and he had to go to the emergency department.
Cycle of invasion
Similar to beavers, the European fire ants shape their environment to suit their needs, creating tunnels in the soil that house hundreds of thousands of workers in a small space, said Normandin.
Each of those ants release a tiny amount of formic acid, throwing off the surrounding soil’s pH balance, making it intolerable for many native species, but allowing some invasive flora, like Buckthorn, to thrive.
“When we went out of this epicentre … we were seeing more diversity of plants,” he said.
The ants often also drive out other animals, including rodents and birds by either stinging them or devouring their young.
Quebec doesn’t consider the ants an invasive species because it hasn’t expanded significantly across the province but Normandin said when that happens, the problem would likely become too big to properly control.
Boiling water versus insecticides
Once the ants have established themselves, they’re impossible to get rid of, according to Normandin.
“You can just limit the expansion and decrease the population,” he said.
Most insecticides don’t work, and the only one that appears effective is Permethrin — similar to Raid.
Vancouver opted for that solution several years ago when the Van Dusen Botanical Gardens was overrun.
Because the ants prefer a shaded, humid environment like the Parc Andromède with a stream running through it, heating up the soil can spell their end in a matter of seconds.
He presented his findings to the City of Gatineau last week and offered several suggestions, including laying down a black plastic sheet on the ground on a hot, sunny day or clearcutting a swath of land between the forest and residents’ backyards to make it less likely the ants would cross the unshaded ground.
Another is a method Idrissi plans to try: lining the edge of a property with concrete slabs. Because of their penchant for shade, they may hide under the slabs, but also lay eggs near the edge where it’s warm.
Then residents can lift up those slabs a few times a year and pour boiling water on the hill.
Idrissi estimates that plan will cost her $6,000 and hopes it will help.
“Otherwise, we have to think about selling and leaving,” she said.
City weighing options
In a French statement to CBC News, the City of Gatineau said it is reviewing Normandin’s recommendations and plans to begin discussions on how to keep the blazing ants at bay.
But the city said it will depend on council’s approval and obtaining any necessary permissions from the province — such as for clearcutting.
“Starting this summer, the city will undertake targeted communication actions to inform residents bordering Parc Andromède of the presence of the European red ant and provide advice to limit its spread,” the city wrote.