They can survive for days after being decapitated, for weeks without food or water.

And according to urban legend, they will inhabit the Earth long after the apocalypse.

Cockroaches.

The old belief that these pests can live through just about anything is proving true in Edmonton.

The despised insects have become immune to the poison most commonly used to exterminate them — and local exterminators say populations are growing.

Though city officials say they have not seen an increase in the number of reports, one pest control expert based in Edmonton said his phone has been ringing constantly.

"There has been a large increase in the number of calls over the past year or two now," Tom Schultz, owner of Edmonton Exterminators Ltd., said during a Tuesday interview on CBC Radio's Edmonton AM. "It's multiple calls a day, as opposed to what used to be a call every day or two. Now you're looking at five to 10 inquiries a day, some days.

"It is really fairly widespread. There really isn't an area of the city where I haven't seen problems."

Insect adversaries

Cockroaches have had millions of years of evolution to develop immunity to threats, and their newest enemy — humans — aren't always a match for them.

Research suggests some of the bugs not only build up immunity to common bait but have also developed a distaste for sugar.

That's bad, since traps coated in sugar are usually the first line of defence against cockroach invasions. Without an effective poison, Schultz said some home infestations have become hard to control.

"We're forced to go back to the old method of spraying and fogging," he said.

"The problem with that is, you chase a lot of them. And you end up having to do a lot more suites in multi-family units because of it, just to encompass the area where they're travelling."

In order to kill off the despised creatures, exterminators have to regularly brew fresh cocktails of chemicals.

A new formula was just brought onto the Canadian market. But it's not cheap. And Schultz said some companies aren't willing to shell out the added cost.

"We're somewhat limited to what's available north of the border here, but they've just introduced a new bait and we're hopeful that it will prove as effective as the old bait when it was first introduced."

"It comes with a cost. The cost of the new bait has doubled, or almost doubled. You get what you pay for is pretty much the old adage. And that holds true for pest control too."

So how do you rid your home of these despised creatures?

Resist the urge to kill them with fire, and save yourself the horror of trying to stomp, stomp, stomp them out one at a time.

Schultz said if traps purchased from the store fail, call an exterminator. And do your research, to ensure you're getting the best price and treatment for your property.

The best way to keep cockroaches out in the first place is to inspect new purchases before you bring them inside.

Schultz said anything imported from a warmer climate — including groceries, used electronics, even your suitcase — could be carrying these unwelcome house guests.