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Specialists aflutter with rare moth find

Sarah Ladik
Northern News Services
Monday, July 20, 2015

The Canadian world of butterfly and moth enthusiasts is all abuzz after a giant silkworm moth was found in Hay River late last month.

"This is one tough moth," said Dave Tilden, Yellowknife resident and amateur lepidopterist, also known as a moth-expert. "The farthest north we've seen them would have been Edmonton, so to see one in Hay River, we have a very substantial increase northwards."

Albert Bourque, regional environmental co-ordinator for the Department of Environment and Natural Resources, found the moth just outside his office June 24. He said he was just walking out the back door when he looked up and spotted it.

"In my life, in my career, I have never seen a giant silkworm moth in the NWT... they are extraordinary as indicators of our changing climate," he said

Silkmoths tend to live about seven days as adults, but can live for months as caterpillars storing up enough energy to transform. A chrysalis was found in Hay River last fall as well, proving that the moth Bourque found was not blown in on a storm, but instead a born-and-bred NWT specimen.

"I think we have cold, tough bugs up here," said Tilden. "In every species, you have a lot of variance."

Tilden also said this moth is only one of several examples of recent unlikely finds. There was a glover silkmoth discovered in Trout Lake and a cicada found in Hay River, neither of which are found often in the territory.

"Things are changing, we're seeing species we never have before here," he said, adding that there are likely many factors that help Hay River's silkmoths survive.

A warmer climate than has been typical in the area is certainly one of them, with the Mackenzie Valley seeing one of the largest jumps in temperature in the world, between three and five degrees in recent years. However, Tilden said a lack of habitual predation is also a possibility. One of the major causes of death for silk worms in the south is wasps laying eggs in their cocoons, killing the caterpillar before it can mature into an adult moth.

"The last time a silkmoth was recorded in Hay River was in 1901 or 1902, and that one was likely blown in on a storm," he said. "This is an extraordinary find. In your backyard, you have made a major discovery."

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