by Anna Hatke and Machaela Kury
Many of us are familiar with the common superstition that having a ladybug land on you is good luck. One of these days, however, you might find that this lucky ladybug leaves behind an odorous smell and even a bite, must be your lucky day, huh? Despite what you might have thought until now, that foul-smelling, home-invading, biter isn’t the only ladybug you’ve encountered. Are you one of those people who identify a ladybug because it has spots? Or one of those who look for its iconic fire engine red coloration and hemispherical shape? Many of you reading this might already know what a ladybug should look like, and can tell which of the insects below is a real ladybug, right?
Before we answer that, however, we must dispel a common misconception: Ladybugs aren’t bugs (Hemiptera)at all, but beetles (Coleoptera). This is why entomologists prefer to call them by one of their alternative common names, the lady beetle. Beetles arethe largest order of insects, identifiable by the pair of hard wing casings that run side by side down the insects’ back. And now for the drum roll. Which ones are lady beetles? The answer is all of them! Despite the differing number/size of spots, and color of the beetle as a whole, they are all indeed lady beetles. What may even be more surprising is that all but one of the lady beetles above are the same species. And if you’re wondering just which one is that problematic, non-native, smelly, aggressive lady beetle, then let us introduce you to the lovely Asian lady beetle (Harmonia axyridis)
The Asian lady beetles, or harlequin beetles, are named so because of their multiple arrays of colors and patterns, ranging from red to orange to yellow and even black, with even more spot variations, or lack thereof! Regardless of their confusing color schemes, Asian lady beetles are easily identified by the “M/W” shape between the head and the wings. Knowing this, see if you can spot which lady beetle above is NOT the harlequin beetle. Found it? This seven spotted lady beetle (Coccinella septempunctata)is one of North America’s natives, as opposed to the harlequin beetle’s origins in Asia, and differs from its Asian cousin in a few ways. But first, let’s address why these Asian lady beetles are here (and most likely here to stay).
Asian lady beetles were initially introduced to the US from Asia as early as 1918, to combat agricultural pests plaguing pecans and red pines. They did their jobs well. Too well! They quickly took over many ecological niches and have undermined the survival of other insects introduced for biological control. Since these non-native ladybugs are such voracious generalists, they end up eating the larvae of parasitoid wasps and some specialized beetles, introduced initially to curb agricultural pests.
If we asked you what bad locally-grown wine and Asian lady beetles had in common, a subjectively valid response could be that both of them are very widespread. Unfortunately, the real answer is far less appealing. It just so turns out that aphids love grapevines, and Asian lady beetles love aphids. When threatened, Asian lady beetles secrete a foul, corrosive, and toxic substance, derived from their blood (technically, hemolymph). Even more, unfortunately, the beetles don’t care that they excrete hemolymph all over the grapes when they are picked and mashed. Beetle blood results in a positively foul-tasting wine. Indeed, a wine for the bravest of heart or lowest of expectations.
Asian lady beetles also have the problematic tendency of nonconsensually renting out your home during the cold seasons. To maximize their survival, they will seek refuge in insulated structures to beat the cold and overwinter successfully. In my house, however, they seem to prefer to die behind our couches. Mass gatherings of lady beetles may only be a minor inconvenience for your vacuum, but for your pets who like to eat things they shouldn’t, it’s a different story. Should your pet accumulate a mouthful of aggravated beetles, they might be subjected to chemical burns from the hemolymph, as in a case in 2008. While your pet will do what it can to remove the beetles themselves, consulting with your vet never hurts.
Knowing now how such a small beetle can pack a potent punch, the next time you see that lucky ladybug, ask yourself, “Who is she?” You might be surprised as to just what company you’re keeping.
This blog got me- there are so many different lady beetles than I expected that go against the stereotypical royal red with a few black dots. I am definitely guilty of loving when the invasive species come around in the springtime, but have a whole new perspective of them knowing they have the potential to ruin great wine! I really enjoyed reading this blog, and when the winter comes around I will be keeping an eye out for these creatures renting my house.
Great article–it’s interesting that I never heard of these Asian ladybugs but can’t stop hearing about the spotted laternfly when both seem to be invasive and bad for our grapes crops.
Fantastic article! I really enjoyed the bit about the grapevine infestations. There seem to be a lot of damaging insect species that were introduced to the US in the early 1900s… I wonder if there was some sort of conspiracy going on?
I love the pictures included in this article! It was great to see a visual of all of these different looking ladybugs, and then to find out they are all the same species. So cool!
It’s funny, a lady bug landed on me yesterday while I was going for a walk and I said to my sister “look, this is good luck!” After this blog, I’m thinking it wasn’t much luck after all! I think the pictures you included were really cool because whenever I think of a lady bug my description is pretty stereotypical, red or orange with some black polkadots. But now learning how many different types of lady bugs or may I say beetles there really are and how they differ is so cool.
Wow, I had no idea that the Lady beetles could affect the grapevines that much. The fact that their pheromones are potent enough to still be nasty when harvesting comes around, is impressive. I might think twice the next time I see a ladybug land on me.
I should have learned my lesson by now to stop assuming that things are native just because I’ve always seen them around. However, I’ve never had a negative run-in with a lady beetle, even when they swarm around our house in the fall. I’ve never been bitten or stunk on…but I also don’t think I’ve ever seen a native lady beetle. That REALLY stinks.
Very interesting article – I’ll be sure to look out more closely for any of them in my house next winter before my dog gets to them first! Oh, and thanks for the heads up about not drinking beetle blood wine!
^^^
I have seen the occasional ladybug before, but I never knew they were such common pests! I also was not aware that ladybugs secrete a foul smelling substance that was harmful to pets, now I know to be more careful for any stray ladybugs wandering around my dogs!
Interesting article, I didn’t realize that lady bugs could be so harmful!
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