British Columbia

There's a 'mass emergence' of mosquitoes in Metro Vancouver and recent rain is to blame, says professor

Rain from about two weeks ago has enabled mosquito eggs to hatch and the insects to come out in full force, according to Ben Matthews, assistant professor in the department of zoology at the University of British Columbia.

'What we're seeing is a combination of very dry conditions followed by a little bit of rain': Ben Matthews

Mosquitoes
Heavy rains from about two weeks ago helped many mosquito eggs hatch, according to Ben Matthews, an assistant professor in the department of zoology at the University of British Columbia — resulting in an increase in mosquito bites people may be getting recently. (mycteria/Shutterstock)

If you've been getting more mosquito bites in Metro Vancouver recently, you're not alone. 

While the region enjoyed some reprieve from the blood-sucking insects because of dry weather, rain from about two weeks ago has enabled the insects to come out in full force, according to Ben Matthews, assistant professor in the department of zoology at the University of British Columbia.

"It's kind of a mass emergence," Matthews said. "What we're seeing is a combination of very dry conditions followed by a little bit of rain."

Mosquitoes breed and hatch their eggs in water. Only female mosquitoes feed on animal or human blood, which they need to produce eggs.

Matthews said mosquito eggs need to complete their development in an aquatic environment.

"They've all been waiting for those rains. And once those rains came, they've all decided to emerge at the same time."

Matthews said eggs hatch into larvae, which look like small worms, and take about 10 days to turn into adult mosquitoes.

WATCH | Professor, Vancouverites on the uptick in mosquitoes:

UBC zoology prof says mosquito eggs were waiting for recent rain to hatch

1 year ago
Duration 2:10
Ben Matthews, an assistant professor in the department of zoology at the University of British Columbia, says mosquito eggs need to complete their development in an aquatic environment.

"And so they don't want to hatch in a puddle as it's drying out. They want to wait until the rains come and then that's going to fill up that body of water to the point that's going to allow them to complete their development."

Matthews said the larvae are now adult mosquitoes, which is why people may be getting more bites.

Meanwhile, many visitors to the region aren't too buzzed about the news.

Olga Rudenko, who hiked Grouse Mountain this week, said the amount of mosquitoes motivated her to go all the way to the top to escape them.

"I was out of breath and my cardio is very bad but those mosquitoes made me go all the way up," said Rudenko, who was visiting Vancouver from Chicago.

Rachel O'Brien, who was visiting from Ireland, said she had been bitten multiple times over the last few days.

"They're itchy … it was just a bit inconvenient. I was worried they'd swell up but thankfully they're OK," she said.

An Asian woman and girl scratch themselves because of mosquito bites.
Health Canada says you can protect yourself from mosquitoes by using an approved insect repellent, wearing loose clothing made of tightly woven materials and wearing long pants and sleeves. (Shutterstock / CGN089)

There are more than 50 species of mosquito in B.C., according to Matthews.

He said the prevalence of standing water is often a good predictor for how much of the bug will be seen.

"So if you're in an area with a lot of backyards, a lot of puddles, a lot of tires that collect water, you may see more local mosquito activity as compared to, say, downtown," he said.

According to Health Canada, insect bites — including those from mosquitoes — can cause itchiness, irritation, as well as potentially serious diseases such as malaria, West Nile virus and Zika virus.

To avoid getting mosquito bites, the agency recommends using an approved insect repellent, wearing loose clothing made of tightly woven materials such as nylon or polyester, and wearing long pants and sleeves.