what kind of swallowtail?
Location:  Bath Michigan
August 8, 2010 6:38 am
Can you tell me what kind of swallowtail this is we live in Bath Michigan I can only seem to find a Thoas picture on web that looks close. There is so much brown on it i cannot identify it. Any help would be great thank you!
Holly VanVoorhis

Giant Swallowtail

Hi Holly,
The Thoas Swallowtail, Papilio thoas, has a much more southern range than Michigan, and it closely resembles the Giant Swallowtail, Papilio cresphontes, that has been reported from as far north as Canada, so we believe your individual is a Giant Swallowtail.  Interestingly, BugGuide devotes an entire page to distinguishing the two species.  The undersides of the wings of both species are typically much lighter than is evidenced in your photo, but this might be partially because of the lighting, the angle of the photo, or possibly because your individual is an older specimen.  Though we were troubled by this coloration, we did locate an image on BugGuide that looks quite similar to your individual.  You may read more about the Giant Swallowtail on the BugGuide information page.

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Unusual coloring on Eastern Tiger Swallowtail
Location:  floyd county, VA
August 7, 2010 3:32 pm
i was recently browsing your site, and was fascinated by Your feature the Tiger Swallowtail Gynandromorph.
Today while taking pictures of the butterflies on my butterfly bush i noticed one of the Eastern Tiger Swallow tails, had unusual coloring. It is the typical yellow, with stripes, but also has patches of dark. i’m curious as to whether it was a normal variation in pattern, or possible a form of mosaic Gynandromorph. Would love any info. i’ve been watching swallowtails for many years, and have never seen one quite like this.
tree

Tiger Swallowtail: Transitional Morph

Hi Tree,
Thanks for sending us your photo of a transitional morph of a female Tiger Swallowtail.  Most female Tiger Swallowtails are yellow with black stripes, but a small percentage are dark morphs, with the yellow ground color appearing very dark.  It is sometimes difficult to make out the stripes unless the light shines through the wings.  Even rarer are transitional morphs like yours, where the female is not truly light or dark, but an intermediary phase between the two typical morphs.  These transitional morphs exhibit varying degrees of coloration and markings.  We have several examples posted to our site from previous years, including a mounted specimen from July 2010.  The gynandromorph is a real rarity, not just among swallowtails, but among all butterflies or insects for that matter.  The bilateral sexual division, where the left half of the insect is one sex and the right half the other sex is especially unusual, though in many insects that do not exhibit extreme sexual dimorphism, many examples may go unnoticed.  The gynandromorph we just posted is an extreme example because the coloration difference between the left and right halves is so extreme.  We suspect gynandromorphs are infertile.

Tiger Swallowtail: Transitional Morph

Thank you so much for your reply and information.  It’s always exciting to see a new or unusual butterfly and be able to identify it! Thank you again!
~tree

Tiger Swallowtail Gynandromorph
Location:  Hillsborough, NC
August 6, 2010 10:48 am
Hi guys,
I work at the Butterfly House at the NC Museum of Life & Science, Durham, NC. Your site is invaluable to us! A friend of ours, who lives locally, sent us this photo of a Tiger Swallowtail gynandromorph, taken last week. I’ve been hoping to see one for decades! If you look closely you can see small patches of wing from male tissue on the female (left) side. What we’d like to know is, does anyone have an idea of the frequency of such an occurrence, especially a near-perfect bilateral one like this?
Richard Stickney

Tiger Swallowtail Gyandromorph

Hi Richard,
Your letter and photograph have us very excited.  On a recent behind the scenes tour our staff was given at the Natural History Museum of Los Angeles, the entomologist, Dr. Brian Brown was very proud of two specimens of butterfly gynandromorphs he showed us, but neither was as spectacular as this Tiger Swallowtail.  Its coloration is even more dramatic since the female left half is also the less common dark morph.  We will contact Dr. Brown to see if he can provide any information on the frequency of occurrence of gynandromorphs in general, and in particular, such dramatic examples.  We are going to have to bump something from our feature section to include this marvelous documentation.  Mom who is visiting from Ohio identified the food plant as Joe Pye Weed, a common roadside wild flower.

Tiger Swallowtails, including rare Gynandromorph, and Ailanthus Webworm Moths nectaring on Joe Pye Weed

Update:  Julian Donahue suggests some resources
August 9, 2010
That is indeed a dramatic bilateral gynandromorph.
I don’t know of a single paper that answers your question about the frequency of this, but you might want to ask someone who works in butterfly genetics.
Try sending the photo and question to some of the following, all of whom work in this field (all are Ph.D.s):
Andy Brower
Thomas C. Emmel [head of the McGuire Center in Gainesville, which probably has a large collection of gynandromorphs)]
Paul Opler
Austin “Bob” Platt
Mark Scriber ["expert" on P. glaucus]
Good luck,
Julian P. Donahue

Ed. Note: What follows is the email we sent to the experts.
Dear Venerable Experts,
I was given your names and contact information by my friend and neighbor Julian Donahue.  My name is Daniel and I am a rank amateur who has been running the pop culture website What’s That Bug? on the internet for ten years.  This amazing photograph of a bilateral gynandromorph Tiger Swallowtail was recently sent to the website from North Carolina.  Can anyone provide any information on the degree of frequency of butterfly gynandromorphs and any information on their fecundity?  Thanks for your assistance.
Daniel Marlos

Paul Opler responds
Dear Daniel,
This is not only a bilateral gynandromorph, but is also showing some mosaic traits.
Beautiful image!
Paul Opler

Professor Andrew Brower responds
Hi Daniel,
You asked about fecundity of these:  I think zero – the genitalia are half male, half female, and I think they cannot engage in copulation.
I don’t know offhand the frequency with which bilateral gynandromorphs occur, but I know by their desirability that they must be rare – perhaps one in 10,000 (a random guess).
Andy Brower
Professor Andrew Brower
Department of Biology
Middle Tennessee State University
Murfreesboro, TN  37132   USA

Mark Scriber responds
Hi everyone;
This is a beautifual specimen. It is obviously nearly a bilateral gynandromorph, but with yellow mosaic color (probably male-like). We sometimes see yellow/dark mosaics (usually in the dark morph female wing background) in offspring our reared tiger swallowtials. I would estimate that these have occurred roughly at rates of 1  in 4,000-5000 offspring. The bilateral gynandromorph tigers are rarer, and might be found roughly once in 20, 000.  We have reviewed the role of hybridization in this phenomenon and some of the historical records in a recent paper:
Scriber, J. M.,  R.J. Mercader, H. Romack and M. Deering. 2009 Not all bilateral gynandromorphs are interspecific
hybrids: new Papilio specimens from field populations. J. Lepid. Soc. (color illustrated) 63 (1): 37-47
Best regards,
Mark Scriber

Brian Brown Responds
September 17, 2010
Daniel,
Sorry I took so long to respond. Gynandromorphs are indeed rare, but
insect populations are so large that they are almost inevitable. In some
insect they are even common. I imagine they don’t do very well in the
environment however, as their lack of symmetry in size would make them
clumsy. If you Google “gynandromorph frequency” you’ll see that there
are many studies on this subject.
Brian V. Brown
Curator, Entomology Section
Natural History Museum of Los Angeles County

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