Kinda sorta bird news here. Some readers may remember from the black swallowtail butterfly ranching that I did last summer that the caterpillars dramatically changed colors as they grew. When first hatched, the black swallowtail cats looked like little bits of finch poop--which I thought was incredibly interesting because unlike monarch caterpillar who stay on the underside of a milkweed leaf, swallowtails hang out on the top of a parsley plant--what a great disguise, who would want to eat something that looked like bird poop?

Well, according to National Geographic, new study by Japanese researchers shows that a single juvenile hormone is responsible for the changing of colors. The hormone levels drop when the caterpillar leaves the bird-droppings stage and begins its green color transformation.

Read the rest of the story here.