Beetle Juice: It’s Not What You Think

Variegated lady beetle – non-native species (Hippodamia variegata)

Ah, the joys of autumn: gorgeous leaf colors, cooler air, blue skies, cozy sweaters…and lady beetles everywhere! As I took advantage of a warm day this week to clean the outsides of the windows on my house, I had to gently relocate at least a dozen of these spotted round beetles.

Whatever you call them — ladybugs, ladybirds, or lady beetles — I’d venture to guess that most everyone is familiar with them. Even those of us who were bug-phobic from childhood can identify a ladybug. They’re one of the least creepy of the creepy-crawlies, right? Who would hesitate to let one of these cuties crawl up on your hand? Nobody, that’s who!

Spotted pink lady beetle (Coleomegilla maculata), a native species

I’ve seen people complaining about “infestations” of ladybugs in their houses, but I kind of like having them indoors when there aren’t many insects left for me to watch outside. But I’ve never had them in large numbers, so perhaps I would change my tune in that type of situation. But whatever your opinion of them, they aren’t a danger to you or your home. And we know they’re one of the most beneficial insects you can have in your garden because they love to feast on aphids and other destructive critters.

Seven-spotted lady beetle (Coccinella septempunctata), introduced from Europe

I was surprised to find out that there are almost 500 species of them in North America alone. iNaturalist shows 227 species in the United States with 30 of them reported in Ohio. (That link takes you to the nationwide search results sorted by species.) I’ve seen eight species so far, and have included photos of some of them in this post.

The top two lady beetles in terms of numbers reported are both introduced species, the Asian Lady Beetle (Harmonia axyridis) and the Seven-spotted Lady Beetle, (Coccinella septempunctata), together making up 55% of all lady beetle reports in the nation. I have trouble identifying the Asian species sometimes because they can have more than 200 color and pattern variations in this single species. Apparently the distinguishing feature is the black “m” or “w” mark on the white portion of the body, as seen here:

Asian lady beetle (Harmonia axyridis), introduced from Europe and now the most common in North America

As usual, I learned interesting things while researching for this article. For example, I had no idea that an individual lady beetle could live for three years, did you? If an insect has a life span that long in a climate like ours, it has to be able to either migrate or somehow survive the cold of winter, right? I found out that some lady beetles do migrate but others stay here by entering our homes or burrowing down into the leaf litter under trees. And that’s yet another reason to consider not removing the leaves around the bases of your trees. Those leaves serve many purposes in the ecosystem, from rebuilding soil to sheltering important insects like these beetles. #LeaveTheLeaves

Just a few of the lady beetles of the eastern United States (from the Evans book below)

Now, what about that “beetle juice” I referenced in the title of this article?

You may already know that the monarch butterfly’s orange and black coloration is a warning to birds and other predators that it tastes really bad. I didn’t realize that ladybugs take advantage of the same survival technique. Yes, their orange and black coloration is an aposematic warning to potential predators that they’re not good to eat. Aposematism is a defensive adaption in which one animal evolves to resemble another that is toxic or otherwise distasteful, to take advantage of that protection. Sometimes it’s a fake-out and the animal isn’t really toxic, but in the case of ladybugs, they really do taste and smell nasty.

From what I’ve read about aposematism, it can involve not only colors but also odors or sounds. And here’s where we get to the “beetle juice” part of this story. Apparently some of the invasive species of lady beetles have become a problem for wine producers because of a foul defensive chemical they secrete from their legs. When they get mixed in with the grapes those chemical secretions actually taint the aroma and taste of the wine. As little as a single drop of ladybug secretions can be noticeable in a swimming pool-sized volume of wine. As this article says, one year the winemakers in Ontario had to dump more than a million litres of wine that had been ruined in this way. You can sit down with a glass of your favorite beetle juice — um, I mean, wine — and read more about that here.

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For those who are interested, here are a few of my treasured natural history resources that were helpful in writing this article. Each of these three books are large and heavy, and full of photos and fantastic detail on all sorts of life forms. I could live happily for years if these were the only books I had left!

Natural History: The Ultimate Visual Guide to Everything on Earth – my copy of this one is the 2010 edition, but a newer one was just published in November 2021 and includes many new species that were discovered since the previous one.

Insects: Their Natural History and Diversity, by Stephen A. Marshall

Beetles of Eastern North America, by Arthur V. Evans

8 comments

  1. I have seen a few of the beetles here but not in the house yet. They are pretty bugs tho. Nice article and info on them.

  2. Fascinating, as always. Your information helped me identify the beetles we get swarmed with as the Multi-colored Asian Lady Beetles. And when I say swarmed, sorry if I upset you, but it’s a horror show that lasts for months. As I’ve read, we apparently have the perfect conditions for attracting them – southern exposure onto a large open field, and a light colored siding. I know they’re helpful bugs on the outside, but if they’d just stay outside I’d appreciate them a whole lot more. And we’ve tried all sorts of home remedies that supposedly work to keep them out.

    • No worries about upsetting me, I totally get it. As I said, I’ve never had to deal with them in my house so I can’t judge anyone who has serious problems with them. Curious though, Bob, do you actually smell them when they come inside in large numbers?

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