Fresh research challenges 'moths to a flame' assumption, says Alberta entomologist

If you thought 'like a moth to a flame' was science, there's some fresh research that just might sting.

"I think it's actually quite wonderful to have what was long thought as a given or truism all of a sudden turned on its head," Ken Fry told the Calgary Eyeopener in a Wednesday interview.

"It's a really elegant study."

The Alberta entomologist was talking about a new paper, Why Flying Insects Gather at Artificial Light, published in London's Nature Communications journal just this week.

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Fry, an instructor at Olds College of Agriculture & Technology, is familiar with the research but wasn't involved in the study.

He said it used to be a given that insects were drawn to artificial light at night. We thought they were attracted to it.

But there's way more to it, and the new research introduces some radical ideas.

"Insects have evolved over hundreds of millions of years with the constant of the night sky being brighter than the dark ground," explained the instructor based in Olds, Alta.

"This dorsal light response — always keep your back to the light and you know that your back is to the sky and your feet are toward the ground."

This new understanding has all sorts of implications.

"We always thought they were being attracted to the light, when, in fact, this paper argues, they are not necessarily being attracted. They saw no direct flight toward an artificial light. Instead, as they are flying through the skies, they are affected by a light. If they fly nearby it, it causes them to turn or spiral," Fry said.

That's, in part, because flying to an insect is as automatic as a lot of our human bodily functions.

"In fact, with their flight muscles, one thought starts the wings beating and then, just like our heart beats all by itself or our breathing.… We don't have to consciously inhale and exhale. We can control our rate of breathing, speed it up or slow it down, but we breathe involuntarily, with our autonomic nervous system," he said.

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An insect's internal navigation system is disrupted when instincts are confused over artificial light appearing below them, when they expect to see it above them. That keeps them in a holding pattern near the confusing light.

"They are expending energy unnecessarily," Fry said.

"They can't get away. Their instinct says they have to keep their backs to the light, so they would not get on with the business because they are stuck circling this light. It also makes them accumulate in higher numbers where a predator could pick them off."

And those predators can also focus on birds and bats, a Calgary wildlife researcher told CBC News in a Wednesday phone interview.

"Lighting can affect birds and bats, especially the migratory species," Melanie Whalen said.

"Migrating birds use moonlight, so artificial lighting can affect them. It disorients them and pulls them off track. They spend more energy than needed and they get confused and exhausted."

Whalen is the director of animal care and wildlife services at Calgary Wildlife. She is also co-founder of the Calgary Urban Species Response Team, a group that rescues and tracks birds that accidentally strike one of the many downtown office towers.

"Bats want to avoid light but because they go for insects near the light, they are now open to predators," she said, adding artificial light kills billions of birds and bats globally every year.

Skies are full of bugs, apparently

Meanwhile, the Olds College entomologist says we can collectively mitigate the problem if we have the will.

"Do we shroud our lights and have the light just go straight down so there is very little chance of them being entrained, or distracted, or affected by our light?" Fry wondered.

"We might need to rethink, what do the numbers mean when we are trapping them? We assumed we were attracting them to the light when it's probably more likely we are just catching what is intercepting that light. They were already in close proximity so we are getting a much smaller volume of space sampled."

That could mean we are massively underestimating insect populations.

"The skies are full of bugs, apparently," he added.