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Eastern Tiger Swallowtail - Female? - Papilio glaucus - male

Eastern Tiger Swallowtail - Female? - Papilio glaucus - Male
Azle, Parker County, Texas, USA
July 29, 2009
Size: 3" wingspan
I believe this is an Eastern Tiger Swallowtail / Female. Would you please confirm? Thank you!

Images of this individual: tag all
Eastern Tiger Swallowtail - Female? - Papilio glaucus - male Eastern Tiger Swallowtail - Female? - Papilio glaucus - male

Moved from Papilio.

Moved from ID Request.

Terrific series of comments on this image! I'm bookmarking it for future tiger-swallowtail reference.

It's very definitely a male. Color pattern is not that of a female.

With the wings spread wide like that, it might push 6 inches, but probably not quite there.

Colorado has both Eastern and Western Tiger Swallowtails. If you were west of the Great Plains in or near the mountains, it would likely be a Western Tiger. East from the mountains in the towns and along the "rivers" of the Great Plains, you can see Eastern Tigers just like the ones in Texas, Nebraska, or Virginia. However, the most common Colorado species in the lower lying areas along either side of the mountains (say Pueblo, Denver, Grand Junction, etc.) is the Two-tailed Swallowtail, which also looks similar. And in the mountains there are also Pale Tiger Swallowtails (usually almost white). So, Colorado has four species of Tigers, and you could see all four in or near to Colorado Springs.

Two-tailed Tigers are the biggest butterflies north of the Tropics in North America, Eastern Tigers (and Giant and Palamedes Swallowtails) aren't far behind, and Western, Pale, and Canadian Tigers are generally smaller than these.

I didn't mention Three-tailed Tigers, which nobody north of Mexico is likely to run across.

I thought only the female had blue HW spots, like so

and the yellow on the male continues down, approximately equidistant from the HW margin as the FW like below.

Are the blue spots on this specimen worn or does the male also have some faint blue spots on HW? Guess I need to rethink my methodology. It's getting late ... not a good time for thinking, anyway. Catch you later.

David is right about this being a male. In my rush to judgement on the color pattern, I failed to notice the terminal "claspers" on the abdomen. Only the males have these.

This is what I love about Bug Guide. Everyday is a learning experience, lessons you'll never find in any guide book.


I think I have a photo of the
I think I have a photo of the underside of this specimen. I will look for one and upload. I don't see claspers on this photo...duh...where are they?

Whatever the sequence of posting
the underside photo does show the male claspers for sure.

As for the blue spots on top - males can have them too (just usually reduced in number and size - but often missing almost entirely). If you look at the rest of the pattern, the female is usually a duller (often more orangey) yellow; dark stripes are wider and usually less "crisp" and less black; the middle band across the front wing often crosses nearly all the way; the outer dark border of the front wing usually has more light scaling included (sometimes almost an added fuzzy yellow stripe); the wings tend to be broader and a bit rounder; females run a bit larger; and, so on. There is a definitely different "look" to the females, as compared to the males.

It is sometimes misleading to look at just one character. It is nice if it actually works, but often such traits involve degrees of difference instead of being always clear-cut and definitive, so the old "taking with a grain of salt" becomes important. A combination of traits usually works best.

Another issue is that some individuals (especially in early spring) look quite different, and are often smaller. A small spring female sometimes looks more like a male than "normal" females do. The male in the linked thumbnail is actually a spring individual (a bit smallish, front wings a bit more pointy, narrower dark markings, etc.), and yes there is a hint of the blue spots thre (usually is at least some).

With a little practice, it's easy to get most of their genders right, but there will always be a difficult few.

Dumb Question
Are the "claspers" what look to the entomologically challenged like the third set of legs?

Not dumb at all.
If you don't know what to look for, it's hard to see :).

Look at the very end of the abdomen, you will see a clear yellow patch that is roughly triangular. This is the left clasper (entomologists call these valvae, among other things). There is one just like it on the other side, and they lay side by side. When mating these help to position and hold onto the female abdomen. You will just see a blunt end on the female here.

All male butterflies have these (works for moths too), but sometimes they are much smaller, and often hidden in a tuft of hair-like scales. However, in some groups, like the Swallowtails, they are large and very easy to see. In some of the Nymphalidae they are very difficult to see, but still affect the shape of the end of the abdomen to a point where you can see a difference most of the time without actually having to poke around.

Yes, she is. I haven't seen one this small before. The ones down here, cast a shadow so large, I usually duck :)

My husband just flunked me in math 101. He says her wing span was more like 6". Sorry! Maybe it's just that female optimism we all have. Her dress size is 6 not 3. =)

Western vs. Eastern Tiger Swallowtail?
How do I tell a Western Tiger Swallowtail from an Eastern Tiger Swallowtail? The one I found here in Colorado looks just like this, but in Colorado, I thought it must be a Western, with maybe some subtle difference.

Underwing Different
A Western's underwing is different, the black stripes are wider (if my memory serves me well) and they are not dimorphic. I think the Rockies are pretty much the dividing dividing line.

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