Calgary

Calgary's hot weather encouraging larger wasp colonies

Insect specialists say there appears to be a spike in the wasp population this year, and the hot weather is likely helping to increase the size of the colonies.

Colony cycle means there are more wasps at this time of year, keeping pest controllers busy

A wasp with yellow and black stripes is seen in a close up as it crawls along a nest.
The intense summer heat this August has likely increased the size of wasp colonies in Calgary, but numbers are not kept annually to track them, says entomologist Rob Longair. (John P. Ashmore/Shutterstock)

Calgary's extreme heat might provide great weather for a picnic, but it's also encouraging larger colonies of wasps to ruin the party. 

"When it's very hot like this, they're very aggressive. You might get stung — they'll go after you," said Mathew Gosselin, owner of Elite Pest Control.

​​​The number of wasp calls he's been getting has tripled since last week, and although it's typical to get a bump in business around this time in August, this year seems to be particularly bad, he says.​

The intense heat in Calgary is likely to help increase the size of wasp colonies during the height of what is typically wasp season, according to entomologist Rob Longair at the University of Calgary. 

And that means it's harder for humans to avoid them. So, he simply advises covering food and sweet drinks at the picnic table.

"It's hard to attribute human qualities to them but they definitely seem to be a little more irritable, if you want to use that term," Longair said.

Wasp management 

In Longair's opinion, the best way to deter yellow jackets when you're enjoying the outdoors is to keep all food and drinks covered.

"If a wasp isn't able to get food in a particular location they'll usually go and look somewhere else."

He also suggests these tricks:

  • Cut off a piece of steak or hamburger and let the wasps dine out! By placing the meat at the end of your picnic table, you'll draw them away from you and your meal.
  • Trap them with a can of pop. Wasps are attracted to sugary drinks and will crawl through the narrow opening of the can and drown. 
  • Don't chase after them with a fly swatter. Longair says some wasps have alarm pheromones — which they release when they think they're being attacked, drawing more of their buddies towards you.