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Asian Lady Beetle vs. Ladybug — How To Tell The Difference Between The Bugs All Over Quebec

They're also called "Halloween lady beetle." Coincidence? We think not. 🐞

Staff Writer
An Asian lady beetle. Right: a ladybug.
Asian lady bettles. Right: a ladybug.

It's said that if a ladybug lands on you, your wish will come true. Well, Montrealers have been spoiled with more luck than they asked for lately, as ladybug lookalikes are invading houses and workplaces this fall. The culprit? the multicoloured Asian lady beetle, or of its official name, Harmonia axyridis.

MTL Blog already told you how to get rid of them, but we wanted to know more about these cute little insects who seem to be aiming for world domination. Marjolaine Giroux, who has been lending her expertise to the entomological-information services of Montreal's Insectarium since 1990, generously accepted to answer our questions.

So, are there really more Asian lady beetles in la belle province this year? And what makes them different from ladybugs in the first place? Let's find out.

How did Asian lady beetles arrive and spread in Canada?

As indicated in its name, the Asian lady beetle comes from East Asia. It was first introduced to North America in Louisiana in 1988.

Since then, the beetle has spread across the U.S. and moved into Quebec in 1995, travelling as far north as the upper Laurentians.

Adults adapt easily and leave their shelter in the spring to mate. The species reproduces a lot, probably two generations per year in Quebec, sometimes three if it's a hot, long summer, Giroux explained.

How do we distinguish Asian lady beetles and ladybugs?

Asian lady beetles are one of the biggest species of their kind in Quebec, varying between 4.8 and 7.5 millimetres long. Their colours vary from yellow, orange and red to black, and they can have anywhere from zero to 20 spots. In Canada, the most common form is orange with 19 black spots, Giroux said.

To make sure you're dealing with Asian lady beetles and not ladybugs, search for an "M" or "W" black shape on the insect's thorax just behind the head.

In both cases, you can make a wish!

Are there more Asian lady beetles in Quebec this year?

Asian lady beetles congregate in October and look for a place indoors to survive our cold winters, which is why you've surely seen more little red and orange creatures this month.

"Each year, they will try to come back and enter from the same location to find shelter in between our walls. They need an average temperature between 15 to 18 degrees to survive," Giroux told MTL Blog.

The entomologist hypothesized that the current brief rise in temperatures could also be encouraging them to come out of their hiding spots.

Though it might look like there are more Asian lady beetles in Quebec in 2022, Giroux said it's impossible to verify.

Should we get rid of them?

The exotic Asian lady beetle is harmless to humans, even though they bite sometimes. Giroux said there are ongoing studies looking at the impact of the introduction of the species on other types of lady beetles in Canada.

But they have an important ecological role, she asserted. The beetle is a predator of aphids and small insects that attack plants, therefore it can be used as a form of biological pest control by agriculturalists. Asian lady beetles are also a food source for many animals like birds.

The Montreal Insectarium explains how to prevent the insects from invading your home online.

This article's cover image was used for illustrative purposes only.

    Charlotte Hoareau
    Staff Writer
    Charlotte Hoareau is a Staff Writer for MTL Blog focused in things to do in Montreal and Montreal weather. She is based in Montreal, Quebec.
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