Butterfly makes early appearance in Alaska

Posted: Sunday, March 02, 2008

FAIRBANKS - A colorful harbinger of summer made an early appearance in Delta Junction last month.

Four-year-old Dominic Austin found a lifeless looking Compton tortoiseshell butterfly in the arctic entry of his family's home on Feb. 20 and presented it to his mother with, "Look mom, a dead butterfly."

"And then it wiggled and he screamed, 'It wiggled; It moved; Look mom - it's alive,"' Jennifer Austin said.

Dominic's find came just as everyone was rushing out the door, but Jennifer delayed their exit long enough for Dominic to retrieve his bug cage and insert the butterfly with a dampened paper towel.

Returning home an hour and a half later, Dominic was overjoyed to find the butterfly upright with its gold/orange and black-patterned wings extended. Eventually he took it outdoors to enjoy the warm afternoon sun.

"That's when the butterfly took the opportunity to fly away," Jennifer said. "Dominic burst into tears and couldn't be consoled for half an hour."

Three days later, Dominic was upbeat and optimistic that his butterfly was safely hibernating again.

"It was beautiful," he said. "It probably will stay alive until summer."

Alaska's lepidoptera expert, Dr. Kenelm Philip, a senior research associate at the Institute of Arctic Biology, isn't as certain.

"It probably won't make it unless it can get back into hibernation, or we have a continued warm spell," Philip said.

The retired scientist, who has been collecting butterflies in Alaska since 1966 and carrying out the Alaska Butterfly Survey since 1970, said the Compton tortoiseshell butterfly is a newcomer to Interior Alaska, first spotted in 2002 in the Bonanza Creek Experimental Forest and also in Wiseman.

"By 2005, it was the single commonest butterfly flying in the Fairbanks area in late summer," Philip said.

The butterfly's numbers diminished some in 2006 but rose again last summer to its previous high.

"They are now flying from Nenana to Delta, and they have been seen in Fort Yukon and Wiseman," Philip said. "I've caught them up the Steese Highway all the way up to Circle Hot Springs."

The Compton tortoiseshell's scientific name is Nymphalis vaualbum, and depending on who you talk to, Philip said, it has a newer name as well, Roddia j-album.

"This species likes to hibernate about five feet above the ground and will die in a cold snap," he said.

The Compton tortoiseshell also is fond of hibernating in houses, garages and sheds.

Philip said he has had calls from home builders and homeowners doing remodeling work who have found large numbers of the butterfly fluttering around when their hibernation hideouts are exposed to heated air in midwinter.

Last summer and fall, Cathy Turner of the Cooperative Extension Service, received numerous calls about the number of Compton tortoiseshells in the area. And much to her surprise she found them at her family's remote trapline on the Nowitna River about 180 miles west of Fairbanks, where it is not unusual to have 60-below temperatures.

"Our cache was filled with them last fall," Turner said.

In natural conditions, the butterflies emerge from hibernation and start flying around in the spring, usually April, and begin laying eggs on willow, aspen and birch trees.

Later, a green caterpillar with long, black, multi-pointed spines and a black head will emerge and begin eating the plant food.

Eventually, a chrysalis will form around the caterpillar and a beautiful, pied-colored butterfly with underwings toned in greys, browns and tans will emerge from the chrysalis in July.

The Compton tortoiseshell butterfly range includes New England and the northern states, and across lower and central Canada to the West Coast with occasional outbreaks as far south as northern Arizona and New Mexico.

"It is usually found in small numbers except during occasional outbreaks," Philip said. "I think that is what we have here."

The Compton tortoiseshell has turned up occasionally in Haines, first in 1982 and a few times since, Philip said.

Even though the butterfly has been doing well since 2002, Philip can't predict if the butterfly will stay or leave.

Philip surmises that the Compton tortoiseshell has outflown its parasites, which accounts for its large numbers in the Interior.

Normally, each female butterfly lays between 200 and 500 eggs, and if it wasn't for parasites to keep them in check we would be overrun with butterflies, he said.

Philip is hesitant to say the population explosion has anything to do with global warming.

"It's possible, but not proven," he said.

In 2005, a dozen Compton tortoiseshell butterflies decided to hibernate in the window casement of Philip's home lab.

"That was a very poor choice for them," Philip said. "They are now in my collection."

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