'A whole summer's worth of mosquitoes': Expert explains Vancouver's recent, itchy surge

If you've noticed a lot of mosquitoes in Vancouver lately, you're not alone.

The bugs have been a talking point at this weekend's CPKC Women's Open at Shaughnessy Golf and Country Club. 

They've also been on the mind of Ben Matthews, an assistant professor in the University of British Columbia's department of zoology.

"The thing that I noticed is that we went for several months with very low levels of mosquito activity – at least out here at the UBC campus," Matthews said in a Zoom interview with CTV News.

He said the recent spike in mosquito activity may be attributable to the weather pattern seen so far this summer.

"We had such a dry summer in the early part that all of the eggs kind of lay dormant in the environment," Matthews said. "And what they're doing is they're waiting to be submerged in water after a rain."

With B.C. still in the grips of a significant drought, months of minimal precipitation left mosquito eggs unhatched, he said. That is, until earlier this month, when there was a period of sustained rainfall.

"What I think has happened is, we had those few days of rain and that synchronized the hatching of what would be a whole summer's worth of mosquitoes and compressed it all into this last period," Matthews said.

Adult mosquitoes can live for several weeks up to as long as several months, he said, adding that whether the current surge continues through the end of September will depend on what the weather does.

"If we don't get another rain event to hatch the next batch of mosquitoes, we might actually see a decline," Matthews said. "If we do see another period of a little bit of rain followed by warm conditions, which is what the adults like, then we could absolutely see another bump in activity going forward."

Other than long sleeves and bug spray, the best way to avoid mosquito bites is to avoid being outside at the times when they are most active, Matthews said.

In Vancouver, that means at dawn and dusk, particularly when temperatures are in the 20s and there's minimal wind, he said.

"You want to avoid areas where there's a lot of standing water," he added. "That's because that's where the mosquitoes breed, and once they emerge as adults, they're actually not great flyers, so you tend to find them within a few hundred metres of where they emerged. So pay attention when you're out and about. See if you can tell what areas of your neighbourhood are most infested with mosquitoes and try and avoid those at periods of highest activity."