A dragonfly lands momentarily on a warm summer day in 100 Mile House. (Melissa Smalley photo - 100 Mile Free Press)

A dragonfly lands momentarily on a warm summer day in 100 Mile House. (Melissa Smalley photo - 100 Mile Free Press)

Hot weather, wildfire smoke impacts insect behaviour

Bugs can be both positively and negatively impacted by wildfires

Those who found their behaviour impacted this summer by the record-breaking heatwave followed by weeks of wildfire smoke are not alone, according a northern BC entomologist.

Insects throughout the Cariboo would have likely been affected by the hotter than usual temperatures in the early summer weeks, followed by heavy smoke – but not necessarily in a negative way, said Dr. Lisa Poirier, of the Ecosystem Science and Management Program at the University of Northern British Columbia.

“Certainly, insects and insect behaviour is pretty much driven by temperature,” Poirier said. “With the warmer temperatures, a lot of things were more active, and there were probably some things that were less active, that went to ground because it was too hot.”

Poirier said certain insects that thrive in warm temperatures would have been more active during the heat wave and the summer months that followed. She received more reports of beetles and wasps than usual, she said, and a report of more dragonflies could also be due to the warmer temperatures.

“It might be that there was good food for them last year, so the larvae survived well,” Poirier explained.

“And definitely because dragonflies are aerial predators, they scoop up insects while they’re flying, and so warm temperatures are good for that fast flight.”

Poirier also pointed out that while it may appear that certain insect populations are booming, that’s not always the case.

“A lot of things were more active this summer and therefore much more visible. They’re out at the same times we are, but it’s not necessarily in higher populations,” she said.

The wildfire smoke that blanketed the region for several weeks in July and August would have likely had a detrimental effect on many insects, Poirier said.

READ MORE: B.C. creates buzz by declaring May 29 the day of the honey bee

She said as intense wildfire seasons become more commonplace in B.C., some in her field are undertaking “increasingly interesting research” as to the impact of smoke on insect behaviour and populations.

Bees are one particular area of interest when it comes to the impact of smoke, she said, noting their activity levels tend to visibly drop during the worst conditions.

“We don’t see bees at flowers on heavy smoke days,” she said. “There’s speculation that the smoke particles are perhaps getting into their breathing tubes and irritating them so they stay grounded. But bees also see their way around, they use ultra-violet and polarized light. But they can’t do that if the sunlight is obscured, it becomes very hard for them to navigate.”

Smoke can also interfere with many insects’ ability to smell their “hosts,” Poirier said, likening their reaction to how many Cariboo residents were forced to close up all their windows and hide inside on the worst days.

“Insects were probably doing the same thing,” she said.

The impacts of wildfires on insects aren’t all bad, however. Poirier pointed out that in areas that didn’t burn too hot, the floral regrowth that occurs afterwards can provide a “real boost to the food source” for many insects.

“A not-too-hot wildfire can actually improve the habitat for many pollinators.”



melissa,smalley@100milefreepress.net

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