Hot, dry weather means fewer mosquitoes in Edmonton but more yellowjackets and ants

It’s been a rare, relatively dry season for the Edmonton area, which means fewer areas of sitting water in which mosquitoes can hatch.

“We’ve had essentially no precipitation all season,” said Mike Jenkins, the city’s “bug guy.” “We had basically no snow (which) turned into no mosquitoes earlier this season.”

For just the second time in about 30 years, the city’s pest management team didn’t need to spray mosquito larvae from helicopters in early spring.

“No appreciable hatching means very few mosquitoes so far this year,” the pest management coordinator explained.

Jenkins adds that mosquitoes’ life cycles are entirely driven by precipitation. But just because we’ve had dry weather so far, doesn’t mean we’re out of the woods yet.

“If we get rain next week, we could easily have mosquitoes coming… There are eggs waiting for the next rainfall.”

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The flipside to the hot and dry conditions is that other species are thriving.

For yellowjackets and ants, this kind of weather helps them get out and forage for food, Jenkins said.

“Their nests are going gangbusters, metabolisms are ramped up… nests are growing exponentially.”

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On their own, these species aren’t problematic, Jenkins explained, but issues arise when their nests get too close to humans.

“They’re actually really beneficial to have around,” he said, adding that yellowjackets collect protein in the form of caterpillars and flies, other species humans consider to be pests. One nest can consume thousands of caterpillars, Jenkins said.

“The issues with them is more when their territories overlap with ours.

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“They get a little stingy when we get too close to their nests,” he said.

Yellowjackets can become more aggressive if their water supply is limited and later in the season when their food source becomes more scarce, Jenkins said.

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Edmontonians are also likely seeing more flies.

“(Their) development is ramped up — considerably so,” Jenkins said.

Usually, a fly’s life cycle is between two and three weeks, but under certain conditions, can be as short as four to five days, he said.

“Their populations can expand tremendously in this type of heat.”

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Edmonton has pest management programs that include monitoring, surveillance and control of many types of bugs. In particular, crews watch out for invasive species, like beetles that target ash or elm trees.

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To discourage wasps and ants from getting too close to your home, associate certified entomologist Jun Bukht suggests cleaning up well after eating in your yard.

“What we can do is rinse our beer bottles, our pop cans, clean our barbecue after the barbecue is done, clean our deck areas.”

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He also suggests filling any cracks in your walls if you suspect insects are finding their way inside.

“Ants and wasps aren’t a bad thing. They’re good for the environment. These wasps are helping our crops, our growth, our environment by getting rid of beetle larvae, other flies, caterpillars and spiders,” Bukht said.

“We don’t want to get rid of them, we just want to stay away from them.”

He also suggests calling an expert if you see a lot of wasps in a high-traffic area and want them moved or removed.

“When they feel threatened or we disturb their nests — when it comes to wasps, hornets or bees — they get more aggressive.

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“They release an aggression pheromone as well — a chemical signal for other wasps to know: ‘We’re under attack, let’s save us, our family, our nest.’ So that can be dangerous.”

Bukht said during Edmonton’s recent heat wave, pest control calls have soared.

“We’re getting literally 150 to 250 calls a day,” he said. “Last year, the average was 50 calls a day.”

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“These are cold-blooded insects, so their body temperature depends on the external temperature. So when the temperature rises in the environment, their body temperature rises as well.

“Now they’re more active, they’re growing faster, they’re more foraging for food… They’re populating more and their life cycle from egg to adult rises dramatically as well by two or three fold.”