This beetle is back to bug you at home, but it won't hurt

When Nancy McLean had supper last week, she found herself surrounded by dozens of tiny, polka-dotted crawlers in her farmhouse in Nova Scotia's Pictou County. 

"It wasn't too disturbing, but it was unusual because these lady beetles are only around and under certain types of conditions," she said.

The biology professor is not the only one noticing plenty of Asian lady beetles, which resemble a ladybug but have a slightly orange tint and a white head. The invasive species often gravitate toward buildings in the fall. 

The ladybug look-alikes were brought from Asia to the U.S. in the 1970s to prey on aphids, another insect that is particularly troublesome in soybean crops.

They have since expanded their reach into the Maritimes, where they have become a common sight before temperatures drop. McLean said the insects become more active on warm days since they use them to find refuge.

"It was a beautiful day on both Saturday and Sunday, so these lady beetles were trying to find a place to hang out for the winter so they would survive," she said.

Robert Johns, a forest insect ecologist for the Canadian Forest Service in Fredericton, said the Asian lady beetle is outside for most of the spring and summer feeding off of soft-bodied insects.

Unlike ladybugs, these beetles congregate and hibernate together during the winter. Johns said the fall is the time when they look for a cozy home for the colder months, which is how they end up inside buildings. 

But the problem with this invasive species, he said, is that it has no natural predators thanks to the smelly, yellowish substance it produces for self-defence. 

"Birds, which would typically be the things that would eat them, they get it in their mouth and they basically spit it out," said Johns. 

This lack of predation means the Asian lady beetle can easily outcompete native species. Johns said some farmers tolerate them for their role in controlling pests because they prey on aphids.

"This [invasive species] is a relatively minor one in the sense that it still attacks things like pests that are on crops," said Johns.

He wasn't aware of any work underway to track their specific numbers in the region. 

Johns said getting rid of an invasive bug species like the Asian lady beetle at a larger scale is "impossible, essentially."