The answer: Carmine
From http://www.msn.com/: "According to the FDA, this red food coloring (also known as cochineal extract) is made from dried, ground bugs . The Dactylopius coccus costa insect is native to Peru and the Canary Islands, where it feeds on red berries. The berries accumulate in the females' stomachs and in their unhatched larvae—which is what gives the extract its red coloring. Carmine is one of the most widely used coloring agents, and food manufacturers routinely use it to turn foods shades of pink, red or purple. Chances are it's what makes the color of your strawberry yogurt or that cranberry drink look so appealing."
I've seen this bug many times. The picture of the cactus and spider, here, was taken by Sarah Olejarz on one of our trips to the Wari Ruins, outside of Ayacucho, Peru. In the lower right side of the picture, you can see white stuff on a cactus leaf. That's the cacoon of the Dactylopius coccus costa spider. The people take it out of the cacoon and smash it's guts the way we used to smash lightening bugs to make a glow in the dark paste (a sad fact that makes me feel very bad for all those bugs from my past). The people then use this gunk to die things. They've been doing this for centuries and it's a part of the vibrant red fabric we all think of when we think of native south american garments. I just never thought about eating it.
Tomorrow, we'll discuss what makes your coffee brown...
(You may read more on this topic and other gross food facts at: http://health.msn.com/womens-health/slideshow.aspx?cp-documentid=100232497>1=31036)