Calgary

Why you might be noticing more wasps flying around Calgary

Wear darker colours and avoid perfume to deter these backyard pests, who have increased in numbers because early eggs are coming of age.

Eggs laid early and summer heat lead to increase in wasp activity, entomologist says

What to do now that it's wasp season in Calgary

1 year ago
4:48
Ken Fry, an entomologist at Olds College, tells CBC Calgary's Andrew Brown how to handle those slightly aggressive yellow and black backyard neighbours as they get active in preparation for winter. 4:48

If you've been out and about in Calgary the past few days, you may have found yourself swatting at the air in an attempt to thwart a seeming increase in wasps.

And unlike the more docile honeybee, Alberta's 14 known species of yellow jacket wasps are known for their persistence — and sometimes aggression.

  • WATCH Ken Fry's full interview with Andrew Brown above.

Ken Fry, an entomologist at Olds College, says you aren't imagining things — Albertans are seeing more of the winged annoyance recently.

This is not due to a wasp boom in 2020. Rather, their numbers tend to increase in late summer, when early eggs come of age.

"Queens start out all by themselves to build a new nest, lay that first generation of eggs and tend to those young," Fry said.

"So the population is really small at the beginning of the season, and as … more kids grow up, then you start seeing more adult wasps out and about.

"By the time we get to the end of July and August, that's when we're seeing the really strong populations."

Hot weather, cold blood

Another factor that contributes to an increase in wasps in late summer is the heat.

Cold-blooded creatures mature more quickly in warm weather, Fry says. This leads to more adult wasps buzzing around during and after the warmest periods of summer, and higher turnover in nests as generations reproduce more quickly.

"They're aging more quickly, so they're developing more quickly — and hence, we're seeing a lot more of them out by this time of the year."

So, it's not a figment of our imaginations: for the moment, there are more adult wasps than usual in our midst.

But are we imagining that they seem more aggressive?

Lack of resources

According to Fry, they are indeed likely to seem more relentless at this stage in the season. But this is not related to some kind of wasp fury — it's about survival.

In competition with other insects and animals for food — and now, an increased population of adult wasps that have young and mature larvae to feed — their persistence is probably related to a lack of resources. 

And while adult wasps are primarily vegetarian and feed off of nectar, younger wasps need protein.

As a result, if you're snacking on sugar or protein outside, they will probably gravitate to you and your food with elevated interest.

"They'll be coming to your burger or your soft drink on the deck, because they're looking for something to drink for themselves, and they're looking for food for their kids," Fry said.

Wear dark colours, no perfume

There are ways to make yourself less appealing to wasps. Fry says wearing bright colours or floral perfume can make you more easily mistaken for a flower worthy of investigation, while darker colours are less appealing.

Flailing your arms or reacting violently if a wasp hovers near you is a way to be perceived as a threat and invite a wasp duel.

Buying commercial traps, or making your own out of a pop bottle and sugar water, is one way to keep wasps at bay, Fry says.

Wasps are most active in warm weather. (Frank Rumpenhorst/AFP/Getty Images)

But before you set out to eliminate your backyard wasp problem once and for all, Fry notes that the role they play in keeping other bugs at bay — and keeping your plants in good health — is worth consideration.

"They put a suppressive force on the other insect populations. So instead of being up to our ears in other bugs eating all our plants, these guys ratchet that down a bit," Fry said. 

"And if they're visiting flowers for nectar, they could incidentally be doing some pollinating as well. So overall, they're sort of an integral part of a good, functioning ecosystem."

With files from CBC Calgary News at 6 and Dave Bell

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