Southern Alberta Newspapers has the buzz on wasps and hornet populations impacting the region

Posted on September 5, 2024 by Ryan Dahlman

By Brendan Miller
Southern Alberta Newspapers

Although traps, kits and DIY projects are effective methods of reducing wasp populations, the region won’t experience much relief from the black and yellow striped bugs until the weather turns.

Wasps, hornets and bees continue to enjoy a constantly hot summer that has led to a rise in numbers as many colonies continue to grow in size as more eggs hatch throughout the season.

Jessica Deacon-Rogers, education programming co-ordinator at the Helen Schuler Nature Centre in Lethbridge, explains that Medicine Hat and surrounding areas typically experience a large population spike of wasps, hornets and bees in August due to a lack of cold weather.

“Because they’re a species that live in colonies there tends to be a large number of them, and the numbers build throughout the summer,” explains Deacon-Rogers. “So when we have a summer where we don’t have a lot of cold weather or really wet weather, they don’t die.”

Typically wasps and hornets are more aggressive than bees and some of the most troublesome native wasp species in southern Alberta include the Arctic and Common Aerial Yellowjacket as well as the Blackjacket, all species are black with yellow and white stripes along their exoskeletons.

The most common hornet species Alberta’s come in contact with in the Bald-faced Hornet that is distinctively black with small white circles around its abdomen near its stinger.

“So we get really big numbers at this time of year, because they’re kind of at their maximum capacity. So you are seeing a lot more of them because there are a lot more of them that are still living.”

Over the winter months very few native bees, wasps and hornets stay alive, generally it’s just a few workers and a queen who are able to survive the cold winter months by burrowing underground.

“The queens will go underground by finding cracks in the ground where they can go down in the soil, or loose soil that they can go and bury themselves in,” says Deacon-Rogers. “They’ll go in debris piles, anywhere you have lots of logs that are piled up, that forms a barrier between them and cold weather.”

Typically once spring arrives the queen will start laying eggs and producing more workers, starting small but growing as the weather becomes more favourable.

Deacon-Rogers explains there are different species of solitary wasp, hornets and bees, but typically the ones causing issues for residents generally come from a large colony.

Food is another reason that wasps and hornets become more active this time of the year as its gets harder for them to find sources of nourishment.

“There’s tons of wasp and hornets because it’s still warm out, it’s not cold at night killing off some of that population, and they’re looking for food,” explains Deacon-Rogers.

Although there is no specific timeline on when to expect populations to decrease, Deacon-Rogers says people will notice a big impact in population around the same time plants start dying off in the garden.

“When your garden is starting to die, when we’re starting to get those first frosts and cooler nights, because they are invertebrates, they don’t create their own heat and so they have trouble living in cooler temperatures.”