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caption: The Atlas moth, nearly 10 inches wide, that turned up in Bellevue, Washington, in July
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The Atlas moth, nearly 10 inches wide, that turned up in Bellevue, Washington, in July
Credit: Courtesy Patrick Tobin

Behemoth moth lands in Bellevue, alarming agriculture officials

One of the world's largest moths showed up in Bellevue, Washington, to the astonishment of the homeowner who found it basking in the sun on the side of his garage — and the alarm of entomologists.

How did an Atlas moth, with massive orange wings wider than an outstretched hand and wing tips resembling a pair of cobras, get from Thailand to the Seattle area?

An advertisement on eBay reveals that someone in Bellevue has been illegally importing and selling live cocoons of the tropical insects online.

Atlas moths are a federally quarantined pest in the United States. It is illegal to buy, keep, or sell live moths, including their eggs, caterpillars, cocoons, and paper-plate-sized adults.

In July, Patrick Tobin got an email from a homeowner in Bellevue who wanted to know what insect was basking in the sun on his garage.

“As soon as I saw it, I knew exactly what it was. Because I teach about this moth in my insect ecology class,” said Tobin, an entomologist at the University of Washington.

“It's an incredibly beautiful moth,” he said. “The snake head on the wingtips, it's just an amazing design, and it's such an incredible example of mimicry.”

Entomologists believe the wingtips serve to fool potential predators into thinking a cobra, also native to the Asian tropics, is poised to attack.

“Even if you aren’t on the lookout for insects, this is the type that people get their phones out and take a picture of – they are that striking,” entomologist Sven Spichiger said in a Washington state Department of Agriculture press release asking for the public to report any sightings of the behemoth moth.

“It's like if all of a sudden you saw a black rhino walking down I-5,” Tobin said of the tropical moth’s appearance in suburban Bellevue.

Tobin asked the homeowner, who declined to comment for this story, to capture the insect. An hour or more after the homeowner first saw it — initially thinking it was a snake — it was still clinging to the wall. He trapped it in a zippered plastic bag, the kind you might store pillow cushions in, and took it inside.

“He was taking very good care of it too,” Tobin said. “I didn't have the heart to tell him that we were about to destroy it.”

Tobin drove over to collect the exotic insect-in-a-bag.

“I stuck it in a freezer as soon as I got back to my house,” he said.

However striking its appearance, the Atlas moth is not welcome here.

The adult moths are harmless. They don’t bite or eat anything — they have no mouthparts. But Washington State Department of Agriculture officials say the moth’s very hungry, leaf-eating caterpillars are a potential threat to the state’s apple and cherry trees.

While butterflies’ and moths’ wings often get dirty and tattered as they flit about, this male moth with feathery antennae was in pristine condition and had probably emerged from its cocoon only recently.

“Coupled with the fact that it was just sitting on his garage for about an hour and a half without moving, that told me it came from nearby,” Tobin said. “I'm pretty sure it came from a local, probably a neighbor or someone in that neighborhood.”

In July, a Bellevue-based account on eBay was selling Atlas moth cocoons for $60 each. The ad is no longer up on eBay, and KUOW’s attempts to identify the seller were unsuccessful.

“This particular individual was bringing in cocoons from Thailand, which is highly illegal, and selling them on eBay, which is also highly illegal,” Tobin said.

caption: An eBay ad selling live Atlas moth cocoons from a Bellevue-based seller in July.
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An eBay ad selling live Atlas moth cocoons from a Bellevue-based seller in July.
Credit: courtesy Patrick Tobin

Adult moths, pinned and mounted for display, can sell for $100 or more on eBay. Selling an Atlas moth is legal if it is already dead.

Tobin says it’s unlikely a tropical forest insect could survive for long in Washington, but it’s better not to take chances.

The Atlas moth’s native range stretches from the foothills of the Himalayas to Indonesia.

“Simla [a city in India’s Himalayan foothills] has a climate not too far removed from ours here, except that they get more rain during the monsoons, so it's not all that far out of line to be concerned about its becoming established,” Rod Crawford, curator of arachnids at the University of Washington's Burke Museum, said by email.

Tobin drove the frozen find to the Washington Department of Agriculture in Olympia, where experts confirmed its identity. They believe it is the first confirmed sighting of an Atlas moth in the United States.

Agriculture officials encourage people in the Bellevue area and beyond to photograph, collect, and report any giant orange moths with spots on their wings to help them determine if this moth was a one-of-a-kind escapee or part of a new population.

caption: An Atlas moth clings to a wall in Bellevue, Washington, in July, with a man's hand for scale.
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An Atlas moth clings to a wall in Bellevue, Washington, in July, with a man's hand for scale.
Credit: Courtesy Washington state Department of Agriculture