In this photo, you can see some kind of fluffy, white specks on the paddle of a cactus. Those are scale insects, microscopic bugs that like to cover themselves in balls of white wax and nibble on prickly pear. You can also see a fingertip smeared in bright red goo. That's what happens when you squish up scale insects. Humans have been doing this for hundreds of years, using the insects' bodies to create a striking, natural dye.
More commonly known as cochineal, the dye turns up in everything from sausage to yogurt. Typically, you'll hear scale insects described as "beetles". They aren't. And that had given me a totally incorrect mental image of what they looked like, so I thought it would be cool to share a couple of Flickr photos that show the insects in their natural habitat — both in their living and, er, more "processed" forms.
Here's a close-up shot of those white cocoons where scale insects live.
And here's a picture of scale insects ground up by hand into a dye powder. If you want to learn more about traditional Mexican dye-making techniques that use the bugs, there's a lot of good info in a travel diary by Amy Butler Greenfield.
Periodically, somebody freaks out about the presence of smooshed bug in the American food supply and you'll see a flurry of outraged posts on Facebook and Twitter. (That's happened three times that I've noticed since I started writing for BoingBoing in 2009.) Now you know what those bugs look like. Want more? I'd recommend checking out an old post by blogger and entomologist Bug Girl that looks at the history and safety of cochineal dye and offers TONS of great links and further reading.
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.