Warm weekend launches invasion of the lady beetles

Not only was the weekend filled with abundant sunshine and warm temperatures, for many homeowners in Minnesota and neighboring areas it was also filled with the sight of swarming Asian lady beetles.

Many people reported seeing lady beetles by the thousands flying around and crawling on the exteriors of their homes.

The bugs are looking for protected sites to spend the winter, and they usually find those spots inside buildings.

The Asian lady beetle is similar to native ladybugs in that their bodies range from yellow to orange to red, with black spots on their backs.

But the most reliable identifying characteristic is a black 'M'-shaped marking behind its head.

This 'M' can look thick, thin or even broken in appearance, according to the University of Minnesota Extension.

The unusually warm weather we had over the weekend, after several chilly nights, caused huge numbers of the beetles to get active in their search for shelter, the Star Tribune reports.

This behavior mimics the lady beetles' habits from their native Asian habitat, according to the extension service, where they fly to cliffs and rock outcroppings each fall to spend the winter.

In the U.S., the beetles seek out sunny sides of buildings during fall, then crawl through cracks and crevices until they find a cozy spot to spend the winter. Box elder bugs also behave in a similar fashion in the fall and winter, U of M Extension explains.

We seem to have a bumper crop of the beetles this year, in part because of our warmer than usual temperatures this fall. The warm weather has also caused a larger population of aphids, which are one of the beetles' primary food sources, according to KOOL 107.

So the beetles aren't all bad, the U of M Extension notes. And they're not harmful, although they can bite at times. They don't reproduce and they don't eat anything once inside.

Unfortunately, though, they emit an unpleasant odor to ward off predators, so when you kill them it can make your house smell.

The Minnesota Department of Natural Resources recommends that you vacuum up any beetles or box elder bugs that get into your house.

To avoid having the dead-ladybug smell linger in your vacuum cleaner, the DNR suggests you attach a trap of gauze or nylon near the end of the vacuum hose, then clean out the traps and dispose of the dead bugs outside. (Diagram below)

To reduce the chances that the insects will invade your house, you should seal all the cracks and openings around the foundation, windows, siding and doors with caulk, and repair any damaged screens.