Beneficial animals

Those Darned Asian Lady Beetles!

My post today isn’t very long, nor very informative. It’s more of an encouragement to all of you who are dealing with red polka-dotted intruders…my arch nemeses…the ASIAN LADY BEETLE.

When the Invader Invades

I’ve already talked about the balance in my house between ladybugs and thrips in the article How to Scare Off Thrips?

But, early in the spring, it’s THE time of year when I can be heard swearing in an ever more colorful way. We’re not talking about balance at this point, it’s a real INVASION.

Those darn lady beetles… Argh!

Lady beetles think they are queens in my home :’( Source: IA DALL-E.

First of all, where do they come from? Clearly not from outside, everything is still frozen!

They spent the winter in my walls, hibernating, sleeping peacefully while benefiting from my heating… Little freeloaders!

Although they sleep, they can’t survive the extremely cold temperatures and that’s why many find a relatively warm place in the fall. The ones that fail, die during the winter (and I’m happy about that).

However, when the temperature rises in the spring, the sun warms the walls, and their cozy hiding place tells them it’s time to hunt for food, they don’t come out the way they came in. Why not? It’s still far too cold outside to go back in right away. Better to stay inside and annoy the humans!

The day we open the walls of my house, we will certainly find thousands of them, dead during their hibernation… It must help the insulation somehow!

So they come out of everywhere: moldings, light fixtures, ceilings. I swear there are no holes to get through, but they find them anyway. And they come out… and come out again… endlessly. I once counted the number of the darn bugs I was sweeping up… at least I tried… I gave up after 300…

Why Are There So Many of Them and What Are They For?

There are so many of them because they are DEMONS!

Like a hydra: you cut off one head and it grows two…

In fact, the real reason is in the ecology of the thing: as it’s an introduced species, it doesn’t have predators in Canada yet. It’s easy to understand why their numbers are so incredibly high. In comparison, native ladybugs are less likely to enter homes, are less aggressive, AND have predators.

The question, now that we understand why there are so many of them, is: why on earth did we introduce this pesky Asian Lady Beetle?

To do biological control in our agricultural fields.


Biological control is the use of natural friends or enemies to benefit our crops. For example, planting the preferred plants of a pest to direct it to that “ disposable ” plant, rather than to our main crop. Or introducing snakes into fields to eat mice (a technique widely used in the United States).

Ladybugs are excellent aphid predators, which is why they were introduced. Is this better than using pesticides? This is debatable. The introduction of invasive species is in the top three of the worst environmental threats. So, in ecology, nothing is ever easy…

Coccinelle asiatique (Harmonia axyridis). Photo: nico_rossi.

How to Get Rid of It?

Hahaha! That’s a good one!

Phot: IA DALL-E.

Get rid of them? No way! There are always exterminators, traps, diatomaceous earth and prayers to the ladybug gods, but honestly, they’ll come back. Unless you plug up every little hole in your house, but then again, I think they can teleport in…

It’s an invasive species, by definition: it’s invasive and hard to get rid of. On a house scale, you can put a balm on it for a season or two, but they’ll come back. On a national scale, forget it, it’s too late to get rid of Asian lady beetles.

The only solution is to wait for them to integrate into our ecosystem.

Sometimes a species invades a habitat, and wipes out all the native species (the ones that are supposed to be there). Sometimes it manages to find a place that doesn’t bother others too much. The good news is that the Asian lady beetle isn’t a disaster that could completely destroy our natural environments. Phew! Some invasive species are worse than others…

The next step is that the problematic species becomes part of its environment: it finds itself a predator! And that’s the moment we’re looking forward to. Will it keep them out of my house? No. But there will be a lot fewer of them. That’s the balance of nature: it takes a while to adapt to a new situation, but eventually it happens (and when I say a while, it can be decades).

A Few Facts About Asian Lady Beetles:

  • They can bite and it hurts. Strangely, they don’t seem to bite everyone: my spouse has never been bitten, but they come and bite me under my pajamas at night!
  • They are a great aphid predator, so they’re beneficial in the garden and in your indoor plants. They consume many insect pests.
  • They stink. The yellow liquid they let out when they are scared is not urine, as we used to pretend when we were young. It’s a form of defense: the liquid stinks and predators don’t want to eat them (honestly, would you?).
  • They have four wings: two for flying and two for protection. The ones on top, the red ones with dots, are actually for protection. The other wings are hidden underneath and are folded.
Photo: Pixabay.
  • The number of points on their back? You can’t count them to tell their age.
  • The white spots are not the eyes. In fact, they are not even on the head! The head is very small and a bit lower.
The eyes are just above the antennas. These are the black balls with a golf ball texture. Photo: Egor Kamelev.

Audrey Martel is a biologist who graduated from the University of Montreal. After more than ten years in the field of scientific animation, notably for Parks Canada and the Granby Zoo, she joined Nature Conservancy of Canada to take up new challenges in scientific writing. She then moved into marketing and joined Leo Studio. Full of life and always up for a giggle, or the discovery of a new edible plant, she never abandoned her love for nature and writes articles for both Nature sauvage and the Laidback Gardener.

5 comments on “Those Darned Asian Lady Beetles!

  1. When one takes the “live and let live” option one fails to consider how long it took the process of evolution for animals and predators to “CO-evolve”. Do you know how many of these animals the existing ecology with its finite resources will support? Will they eat ALL aphids and then some species of bird or insect will find food and die out? Are you willing to have this insect, which creates novel problems for humans, and we have no idea when the exponential population growth will stop (most likely when they have depleted the food supply for themselves and the species that used to depend on them). So. I respectfully disagree. I found a photo on the internet of a person sweeping a veritable pile of these insects with a push broom. Not in my house, and not in my ecology. I feel the moral and responsible thing to do is…smush…every time I find them. At least I can fill the role of the absent predator and maybe slow down the biological mess we have made by the rapid mixing and stirring of millennia of organized evolutionary relationships…into a highly unpredictable biological stew…the rising costs of these introduced plants and animals in protection of natural areas, and protection of our own food supply, as well as health costs for things like giant hogweed are ginormous. We need to be responsible for our actions and not give cavalier advice when we don’t really understand the consequences of our actions or how bad this will get.

    People screamed when the Brown Spruce Longhorn Beetle was introduced to Halifax and started killing spruce in a public park…people screamed when attempts were made to control it (since this involved cutting down some trees). Now our forests are ravaged. I study this stuff deeply, and admit I don’t know all the answers…but I became a native plant gardener (and defender) because this is the best way I can imagine to both fight climate change and the massive and largely unnoticed because of our lack of deep interest in the plant world) numbers of introduced species. The rewards have been increasing native biodiversity in my garden and richly personally rewarding to know I offer a kind of refuge in my back yard. I admit it is hard work, both mentally and physically. I can’t shrug my shoulders, and have no problem admitting or understanding how little humans know about ecology and the long term impacts of our actions. Subtractive gardening is what I call it, targeting the most obviously harmful invasives as a priority. One that invades my house is on that list.

  2. Connie Hart

    Your opening photo and the last 2 photos aren’t Asian Lady Beetles but also another introduced invasive species Coccinella septempunctata – Seven-spotted Lady Beetle. Plus all ladybugs can bite and excrete a foul liquid to deter predators.

  3. Ok – your article twiged something and got me to look at my pictures on my ipad here. Turns out i have photos of these bugs mating in our apple tree! At the time i thought the white spots was camera flash and i tried different angles to get rid of it but alas could not. So it wasn’t ladybugs having a moment; it was demons showing off. That was four years ago and i find out now thanks to your article.

  4. Audrey -great post. Tell us more. How to tell the difference between native and invasive ones. Who are their predators? And a couple more pictures,please. Thanks for all your posts.

    • marianwhit

      There is a range of variety and they can be found by doing an image search on Google for them. Also Search this string for a very worrisome scientific study on the impact on native animal populations. “Asian lady beetles use biological weapons against their European relatives”

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