Wednesday, September 17, 2008
Black Swallowtail Caterpillar
I found this caterpillar in my dill earlier in the summer, and lucky for me it's still there! I hope it stays and gifts us with the opportunity to watch his/her transformation. It's going to be a gorgeous Black Swallowtail. Also called the Parsley Caterpillar, young Black Swallowtail caterpillars are black with a white saddle, later becoming smooth and green with black bands and yellow spots, growing to approximately 2 inches. It has an orange osmeterium, a fleshy organ found in the prothoracic segment of caterpillar larvae of Swallowtail butterflies including Birdwings. This organ emits smelly compounds believed to be pheromones. Normally hidden, this forked structure can be everted when the caterpillar is threatened, and used to emit a foul-smelling secretion containing terpenes. These chemicals are bad tasting to predators and vary from species to species.
The Black Swallowtail eats Queen Anne's lace, carrot, parsley and dill, of course. It overwinters as a chrysalis and is found in southern Canada and throughout the eastern United States, as well as the south-western states and Mexico.
Isn't it beautiful? :)