‘Ew, those are caterpillars’: Clusters of crawlers turning heads near Edmonton

People in and near Edmonton might start seeing an increase in the number of caterpillars around. As Connor Hogg reports, the bugs are mostly harmless.

“First you notice the cluster and you get close to look at it, then you realize you’re actually completely surrounded by them.”

It’s how Chelsea Kaps described discovering a growing movement in Beaumont in an interview with CTV News Edmonton on Tuesday. She said she was out walking her dog in her neighbourhood when it first caught her attention.

“We got closer and we’re like ‘ew, those are caterpillars,’” Kaps recalled.

“They’re all over the branches and they’re all over the concrete,” she added after parking her car under a tree crawling with the insect while out shopping on the north side of the city.

Mike Jenkins, a scientist with the City of Edmonton, identified the bug in a photo sent by CTV News Edmonton as the forest tent caterpillar. He said the species is native to Alberta and caterpillar outbreaks happen every 10 to 13 years.

“Lac La Biche had outbreaks a few years ago. There was a huge outbreak in the Peace region several years ago, but we haven’t seen one in Edmonton basically since the late ‘80s,” Jenkins said.

He added that Edmonton is also getting increased sightings of the creepy crawler, with most reports coming from the south side of the city.

“We’ve seen handfuls of forest tent caterpillars every year for many years, but this is the first time we’re actually seeing numbers starting to kind of ramp up,” he said. “That’s usually the early stages of the outbreak.”

“It’ll probably be a couple years until we start seeing the houses completely covered with an entire curtain of caterpillars.”

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According to Jenkins, the caterpillar clusters tend to be concentrated near poplar trees, which are a favourite food source for them. He says they will also go after other trees, too, like ash, Manitoba maple, oak and fruit trees.

And while a large number of caterpillars can strip a tree of its bark, Jenkins said the insect is harmless and not bad for trees.

“Deciduous trees in particular are well adapted for getting defoliated by caterpillars,” he said about the co-evolution of forest and caterpillars. “Even during a massive outbreak in which thousands and thousands of acres of trees get completely stripped by the caterpillars, the trees are still actually able to photosynthesize.”

Jenkins added that the bug is generally harmless to people and their homes, with the exception of becoming a potential hazard if large numbers start crawling on roads.

“They can actually create a hazard as they’re all moving together and someone drives over them. The squished caterpillars can be basically a caterpillar slick,” he said, citing cases in the past.

“With the eastern tent caterpillars, (there) have been major highway-closing accidents due to caterpillar migration.”

But he said the last few times there was a potential caterpillar outbreak in the Edmonton area, it was put to a stop by competition with another insect for food and by cold weather late in the spring.

“Every time we’ve seen these numbers kind of going up the last several times, something has kind of broken the cycle and that could happen again,” Jenkins added, saying it’s too soon to tell what will happen with the latest crop of caterpillars.

For now, his advice is to not be bugged by them.

“It’s pretty safe to touch them. You can have them on your hands crawling around. They’re actually quite soft and velvety to pet.”

Something Kaps said is a pass for her, while stopping to get a closer look at the caterpillars by her parked car in Beaumont.

“I wouldn’t touch them. I heard that they’re harmless, but I still wouldn’t touch them.”

With files from CTV News Edmonton’s Connor Hogg