Subject: Tiger Swallowtails
Location: Western Kentucky
September 9, 2012 6:47 pm
I have a question about the Tiger Swallowtails. I know there is an Eastern, a Western, light phase, dark phase and so on. I live in Kentucky and around the area I have seen different colors on the Tiger Swallowtails. I wondered why some have a lot of blue and some have none at all. I am including three shots of the Tiger Swallowtails from around the area. Two are from 2010, and one from 2011. I have wondered about the reason for the areas of blue on some.
Signature: Janet Fox
This is a very interesting and complicated question and we will try to the best of our ability to answer it correctly. There are at least five recognized Tiger Swallowtail species: Pale Tiger Swallowtail, Western Tiger Swallowtail, Canadian Tiger Swallowtail, Appalachian Tiger Swallowtail and Eastern Tiger Swallowtail as well as a similarly marked western species known as the Two Tailed Swallowtail. We believe your individuals are Eastern Tiger Swallowtails. Males lack the dusting of blue scales on the lower wings that are present in the female, so the blue markings can be used to differentiate the sexes. You can get a full explanation of these differences on BugGuide. To further complicate things, BugGuide reports hybrids that might occur where the ranges of the different species overlap.
Thanks so much for taking the time to answer me. I have been taking pictures of bugs for a few years now. I had so many that I could not name and I spent a lot of time trying to find them on your site. I broke down and bought a Kaufman Field Guide to Insects of North America. I still have a couple I can not find in there. But I am happy to report most of my photos do have names. Your site is a great resource to me for information and confirming my possibles. When I started taking random pictures of bugs, I never realized there were so many kinds. I also didn’t know so many were so pretty.