Experts call appearance of butterflies "major biological event" - NBC Right Now/KNDO/KNDU Tri-Cities, Yakima, WA |

Experts call appearance of butterflies "major biological event"

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KENNEWICK, Wash.-- Experts say the appearance of pine white butterflies in the Tri Cities for two years in a row is a major biological event.

The butterflies usually live in forests in Central Oregon but weather systems sometimes carry them to the Tri Cities.

Some experts say their appearance suggests they've established a colony here. Others would rather wait and see.

"They have an annual life cycle so they only come out once a year. So, it'll be interesting to see next August whether we have pine whites again in the Tri Cities," says WSU Professor of Entomology Dr. David James

While James says it's unlikely the pine whites have established a colony, he doesn't rule out the possibility that some could lay eggs here.

However, he still thinks the pine whites existence here is only temporary.