October: That Orange Thing

Black swallowtail osmeterium
The orange thingy on the head of this black swallowtail caterpillar has a wonderful name: osmeterium. It’s a sense organ that comes out when a caterpillar is threatened. It may also spread smelly pheremones. Okay, so I just like the word osmeterium. We grow bronzen fennel and parsley to feed these creatures. Mostly they show up on the fennel.