Alberta entering prolonged mosquito season unseen in decades as heavy rain triggers egg hatch
The province is experiencing mosquito numbers not seen since 1990, with sustained rainfall over weeks creating ideal breeding conditions across habitats.
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Alberta is entering a prolonged mosquito season unseen in decades, with entomologist Ken Fry reporting he was "eaten alive" while golfing in central Alberta this week. Mike Jenkins, a biological sciences technician for the City of Edmonton, said the last time Edmontonians experienced such vigorously high mosquito activity was in 1990.
"I got so many mosquito bites. I actually got one on my tongue back then," Jenkins said. "She took off before I noticed that she was feeding on my tongue. But, yeah, that was not a fun one."
Heavy rainfall across Alberta is the culprit. In 1990, rain had been falling since May; this year, mosquitoes have been emerging in abundance since heavy rains arrived in late June. "It's been probably years since we've seen sustained multiple weeks' worth of rainfall," Jenkins said. "There's water in places I haven't seen in literally decades. The mosquitoes are being produced from those habitats."
Mosquitoes lay eggs near bodies of water, and those eggs can remain dormant for up to a decade. When water levels rise, the eggs hatch underwater into larvae that resemble small worms, developing into adults within 10 days. Because Alberta has experienced drier summers in recent years, dormant eggs from previous cycles are now hatching en masse.
Females lay approximately 100 eggs at a time. Once fertilized by males, hungry females seeking protein to grow eggs begin feeding on blood — the least enjoyable part of the season for humans. Entomologist Fry noted that Alberta's mosquitoes have evolved to feed on deer, moose, horses, and cattle. "If you wear dark and rough clothing, you'll look like a cow," he advised. "But if you wear light-coloured clothing, then you look like a flower. And the females also like nectar."
Bug spray has flown off shelves, and Albertans have swapped tips on social media for finding stock. The City of Edmonton is trying to reduce mosquito numbers by spraying pesticide along roadways. If rainfall continues in coming years, the flies are set to return again in abundance — the eggs now being laid will refill the dormant egg bank for future seasons.
The facts
When was the last time Edmonton experienced mosquito numbers this high?
1990 was the last time Edmontonians experienced such vigorously high mosquito activity, according to Mike Jenkins, a biological sciences technician for the City of Edmonton.
What triggered the current mosquito outbreak in Alberta?
Heavy rainfall across Alberta starting in late June created ideal breeding conditions. The sustained rainfall activated dormant mosquito eggs that had been lying in various water habitats for years or even decades.
How quickly do mosquito eggs develop into adults?
Mosquito larvae develop into adults within 10 days of hatching underwater.
How many eggs can a female mosquito lay at once?
Female mosquitoes lay approximately 100 eggs at a time.
