A creeping invasion of a new - and potentially painful - pest has already been charted in a North Vancouver neighbourhood.
European fire ants - a species of increasing concern in the Lower Mainland - have been found in several yards and a road allowance near Deep Cove Park off Rockcliff Road.
Municipal staff are monitoring the area and trying to prevent the spread of the aggressive ant species, which can make using backyards and park areas impossible.
So far it's not clear if the ants are in more than one location on the North Shore.
But the growing numbers of fire ant colonies in Metro Vancouver neighbourhoods is on the radar of both environmental and municipal staff, who are hoping to work with residents to stop their spread.
Unlike other ants, the introduced species is known for its unusual and aggressive behaviour - including swarming and repeatedly stinging anyone unlucky enough to disturb an underground nest.
"It stings quite readily," said Robert Higgins, a fire ant expert and professor of biological sciences at Thompson Rivers University who has been studying their spread in the Lower Mainland.
Once fire ant colonies are established, "you can't let kids out in the backyard," said Higgins. Backyard barbecues and even mowing the lawn are likely also impossible on an infested property.
In North Vancouver, Higgins first identified the fire ants in one neighbourhood a year and a half ago and confirmed it again last summer. But the ants have probably been there at least a decade, he said.
"It takes only moments to find fire ants in this area, and one backyard had four nests within one square metre," wrote Higgins in a report on the North Vancouver ants. "This has made it impossible for the homeowner to use the yard recreationally and even challenging to mow."
Higgins said he's hoping to get back to the neighbourhood later this summer to check on the nests, but there is no indication anything has changed.
The European fire ants aren't the same species as the better-known fire ants found in the southern U.S. states, said Higgins.
The European fire ants were first introduced to the east coast more than 100 years ago, but only became a problem in the last 10 to 15 years, he said, when colonies started reaching high densities in some places. When that happens, the ants seem to know they control the area, said Higgins, and are willing to aggressively drive off anything that impedes their progress.
The small red ants are also more aggressive when temperatures reach about 20 degrees.
Adding to the problem is that they are difficult to control with pesticides, said Higgins. Most ants sent out to defend the nest are the oldest and most expendable ants, leaving the healthy ants unharmed. Higgins recommends mixing up a low concentration of Borax and sugar as the best means to try to control them. That way, the bait doesn't kill the ants before they deliver it back to the nest. Because the insects are so unpleasant and difficult to get rid of, identifying exactly where they are is a touchy subject.
So far there is no requirement, for instance, to inform prospective house purchasers of an infestation.
