The Ladybugs' Block Party

by Jennifer Frazer on September 27, 2009

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This weekend I climbed to the top of Green Mountain for the first time. If you are familiar with Boulder, it is the right mountain of the two bearing flatirons visible from town. But the top didn’t just contain the usual stunning views. As I neared it, I noticed a few small swarms of lady bugs. Notice the plants on the left. Here’s what was on those plants:

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And as I climbed higher, I steadily saw more. Soon the ladybug population exploded beyond all reason. The air was filled with ladybugs flying to and fro, landing on our packs, clothes, and faces. The orange masses in the following pictures are not orange Xanthoria lichens. They are carpets of ladybugs.

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This guy clearly cannot believe how many ladybugs he is seeing. Either that, or he is laughing at the lady bugs on the photographer.

After consulting the interwebz, it seems what we saw were not native ladybugs, but the Multicolored Asian Lady Beetle, Harmonia axyridis. Unlike our native and presumably sober, upstanding, red-shelled and red-blooded All-American ladybugs, these introduced (from Asia for pest control) guys/gals have multi-colored and variously spotted orange shells. They swarm at the end of summer to find cracks and crevices in which to kick back, order pizza, hook up the cable, and watch 800 hours of the Home & Garden network until spring. Life’s rough sometimes.

In case you were wondering, it’s more proper to call ladybugs “lady beetles” (the scientifically PC term), because true bugs are in the taxon Hemiptera, and our friends are not bugs, but beetles, which form the massive taxon Coleoptera. The most distinguishing character of the beetles are those hard wing covers, known to science by the beautiful name “elytra” (sing. = elytron), which sounds as if it should be the name of a character in a play by Aeschylus. Here you can find the tree containing Coleoptera (the beetles) at the Tree of Life Web Project.

To give you a feel for the kinetics of the situation, here’s a video of the same event taken above Boulder somewhere at the end of July. Next time you want to terrorize the local aphid population without actually buying a gallon of lady beetles, just show this film in your garden.

5D and EX1 Lady Bug Swarm from Michael Ramsey on Vimeo.

And finally, just for kicks, here’s the picnic that inspired this “block party” — a blast from the past for some of us:

{ 2 comments… read them below or add one }

Reed E September 28, 2009 at 11:55 pm

For the past several weeks, I’ve been contending with population explosions of Boisea trivittata (Boxelder bug) outside my home.

I’m glad they aren’t as cute as lady beetles, otherwise I’d feel guilty for trying to wipe them out.

Jennifer Frazer September 29, 2009 at 9:03 am

Yeah, we get those at the Foothills Lab too in the fall and winter. I saw one yesterday crawling across my window. I leave them alone for the most part as they are harmless, but they do form into somewhat of a pesky herd late in the fall. It’s fairly disconcerting to see them migrate across your desk or to pick up your teacup to find a boxelder bug floating in it. I still don’t have the heart to kill most of them. : )

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