Published August 20, 2010, 07:21 AM

Butterflies: Casualties of the skeeter war in upper Red River Valley

Parts of Grand Forks and East Grand Forks were abuzz with speculation Thursday after some residents woke up to a strange sight — dozens or even hundreds of dead dragonflies and monarch butterflies on lawns and sidewalks around the community.

By: Ryan Johnson, Grand Forks Herald

Parts of Grand Forks and East Grand Forks were abuzz with speculation Thursday after some residents woke up to a strange sight — dozens or even hundreds of dead dragonflies and monarch butterflies on lawns and sidewalks around the community.

Stuart Kovar, foreman at East Grand Forks Public Works Department, said this was probably caused by the mosquito spraying done by both cities Wednesday evening.

“It’s not that we want to hurt them or anything,” he said. “It’s just the way the chemicals worked.”

Kovar said the chemical now used to kill mosquitoes on both sides of the river is safe for people and pets, but officials recommend staying indoors while crews are spraying mosquitoes.

The chemical works by attacking the nervous system of a mosquito after being absorbed into its body. It breaks down quickly and is completely gone within 24 hours, Kovar said.

Still, the war on mosquitoes does have unintended consequences. He heard from several people Thursday wondering why there were so many dead bugs around the city.

‘Doing damage’

Kovar thinks it’s getting noticed because there seems to be more butterflies and dragonflies than normal this year. He’s been spraying mosquitoes for about 17 years but said he can’t remember a year with so many bugs.

“Since we have so many of the species around, it’s just that our chemical is showing it’s killing them anyways,” he said. “There isn’t much we can do about it. We can change all of the chemicals, and it’s still going to kill them.”

Laurie Arnason said she wondered what was going on after she took a jog near her Grand Forks home on Belmont Road.

“I was out this morning and I saw three butterflies in the grass dead,” she said. “I thought it was very odd to see these monarchs because they looked like they were healthy.”

Arnason, a fourth-grade teacher in East Grand Forks who helps manage a butterfly garden at Central Middle School, has seen more monarchs than usual in the past couple of weeks.

While she’s glad to notice that upward trend, she said the attempt to eradicate mosquitoes could lead to butterflies taking a big hit.

“I think I’ve seen more monarchs than ever, and I think that’s a good thing,” she said. “But now when they get to the stage of being butterflies, our city’s doing damage.”

Monarch butterflies are migratory insects that fly as far north as Canada during the spring. Arnason said once they get here, they lay eggs that will eventually become caterpillars that transform into new butterflies that fly south to Mexico for the winter.

She said there could be more butterflies in the skies because of more abundant milkweed, a vital plant that grows in ditches all over the region and serves as the monarch larva’s source of food.

But Arnason said the fate of the monarchs will come down to deciding if keeping pesky and potentially dangerous mosquitoes to a minimum is worth the unintended consequences of the chemicals.

“It’s good and bad,” she said. “The taxpayers are getting what they’re paying for and you can enjoy your yard.”

“I would say if they’re killing off the butterflies, they’re doing damage,” she added.

Kovar said his department has to be on alert because it’s the peak season of West Nile virus, a sometimes-fatal flu-like disease spread by mosquito bites. August and September are often the two “toughest” months for the Culex tarsalis mosquito, the type most likely to transmit the virus in the region.

“We don’t want to destroy the butterflies, and we don’t want to destroy any other bugs if we don’t have to,” he said. “Our goal is to keep the mosquitoes away so people don’t get sick.”

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