Global Courant
mosquitoes.
They are thirsty leeches that annoy those who venture out into nature, feasting on their salty source of life while leaving red, itchy bumps behind.
And this year, the pesky bugs across Canada seem worse than ever.
Those who have wondered about an increase in mosquitoes may be right, according to Laura Ferguson, an assistant professor of biology at Acadia University in Nova Scotia.
“It’s definitely been a trend to some degree that people are noticing anecdotally,” she told CTVNews.ca in an interview Friday. “New Brunswick, in particular, has seen major outbursts in mosquito populations in recent years, especially this mid-to-late spring.”
Why mosquitoes can be worse than usual in some areas has more than one answer.
WHY MOSQUITOES ARE SO BAD THIS YEAR
Ferguson is working with a team to study mosquitoes, understand the different species and track their abundance in North America.
“It’s for a few different reasons why we’re seeing more mosquitoes than we may have had in the past few decades or so,” she said.
The first contributing reason is that there are more mosquito species than in years past.
Different types of human goods travel around the world. They then breed in their new homes, creating populations of specific species of mosquitoes where they had never existed before.
“Here in Nova Scotia, for example, we didn’t have (kind of) a few decades ago — it came from Japan in tapes, we think — and it just exploded all over the province and you can find it everywhere now,” Ferguson said.
In addition, Ferguson said, warmer winters caused by climate change allow mosquitoes that would die off in the winter to survive and reproduce.
In addition to being able to survive the milder weather, some types of mosquitoes can reproduce faster in warm temperatures due to the type of insect they are. Ferguson says mosquitoes are ectotherms, meaning their regulation of body temperature depends on outside sources like the sun.
Precipitation also plays a role in how well mosquitoes can survive, as they lay eggs in standing water.
Ferguson said if it’s a particularly dry spring, there may be fewer mosquitoes around, depending on the species. Others lay eggs in the fall, so there would only be a big drop in mosquito numbers if the previous year was dry.
Another theory that needs more research, Ferguson said, is the diminishing effects of the chemical dichlorodiphenyltrichloroethane (DDT), which was historically used to control insects in crops, but was phased out in the 1970s due to its damage to other species.
Despite this, the chemical can still be found in water and circulates in ecosystems.
“Those kinds of residual effects from these really persistent insecticides may have also suppressed the mosquito population for several decades,” she said. “And now we’re experiencing a little bit of this recovery in these populations as these insecticides and their effects in the environment begin to wear off.”
WHAT CAN BE DONE ABOUT MOSQUITOS?
Unfortunately, all of these factors lead to an increase in mosquitoes, a problem with no quick fixes.
“I think for the most part we just have to figure out ways to protect ourselves from contact with mosquitoes because they’re part of the ecosystem,” Ferguson said.
“Regularly it will be things like hanging out in a screened porch instead of directly outside, and causing you to dump standing water all over your yard.”
Using repellents like DEET and some natural oils can help when you’re in the woods, Ferguson said.
“Wear light colors, long sleeves, things like that to reduce the part of your body exposed to potential bites,” Ferguson said. “That sort of thing is pretty much our best bet to avoid our contact with them as much as possible.”
