An Asian mosquito that somehow caught a ride to Minnesota is moving across the metro and will start nibbling on people in the east and north suburbs this summer.

What is it? The japonicus, or Japanese rock pool mosquito. The japonicus is a durable species that lays eggs that can survive a Minnesota winter, and like other species can carry LaCrosse encephalitis and West Nile viruses, said Mike McLean of the Metropolitan Mosquito Control District.

Where did it come from? The japonicus, native to the colder northern parts of Japan and Korea, hitchhikes in tires and other containers that trap water.

Great, another mosquito species. Are we doomed? Minnesota now has an estimated 51 mosquito species, many of them "exotics" that travel from distant habitats. "I don't think the average person will notice more mosquito bites per hour because of this," McLean said.

How widespread is it? The species was found last year in large numbers in Ramsey and Dakota counties, and it showed up in other areas south of the metro in the past couple of years. It was found last fall in northern Washington County and is moving west into Anoka County, McLean said.

Is it dangerous? "Like anything else, when you introduce a species you have to pay attention to it awhile to see how it behaves," McLean said. "It doesn't really raise any big red flags, but it is something we want to pay attention to." While the japonicus species isn't considered a primary carrier of the West Nile virus, it can be a nuisance, he said.

So what's the big deal? Because the species is new to Minnesota -- and suddenly appearing in county after county -- it's attracting attention from scientists. "From a biological standpoint, this is a really interesting occurrence," McLean said. "We can study it to see how it spreads. How fast does it move from one month to the next?"

How do we keep it away? Samples last summer and fall were found in storm-water ponds, water gardens and other places where water collects. "They do really well in the sort of junk people leave laying around, tires and debris," McLean said. "Dump the water out of things once a week in the summertime and you'll prevent them in yards and neighborhoods from being a problem."

Kevin Giles • 612-673-4432