Eastern Tiger Swallowtail (P. glaucus) (dark phase/form)

[Trehopr1]

The Eastern Tiger Swallowtail (Papilio glaucus) is a wonderful
and large butterfly to behold as a visitor to one's garden or in
a clover-laden field. Aside from these places the butterfly is
only glimpsed as a passer-by with a strong and un-even flight
path.

Males are what most people typically encounter in flight or
puddling. However, the usually larger females (occasionally)
seen pollinating are a very welcome sight in the tell-tale
blue coloration of their hindwings.

Eastern tiger swallowtails have females which occur in 2
diffrent color (phases) or forms; along with a rarely seen
intergrade or "transitional" form.

It has been remarked in literature that the "dark phase"
is more prevalent in southern states as it has taken on an
(appearance) similar to the Pipevine Swallowtail (Battus philenor)
for reasons of mimicry --- as the pipevine is distastful and/or
poisonous for would-be predators to eat.

Here in Illinois both color phases can be readily encountered
(mostly in wild spaces). These large and quite colorful butterflies
are real attention-getters wherever they may be seen.

Dark-phase females are particularly interesting for their many
SUBTLE "variations". Some have a (blue) coloration which may be
bolder OR more extensive than in other examples. Some have
longer-thinner tails whilst others appear fatter (more spatulate)
and somewhat shorter. The large red-spots present on the hind
wings may be bold, reduced, or bi-colored. And still yet, the
outer marginal spots/markings vary as well.

So, basically all these things make for a particularly curious
subject to catch a series of (where possible). Below, I show
a nearly finished (2nd) drawer of this color phase.



All of my specimens have been acquired as wild-captured stock.
All told, my 27 specimens thus far represent captures made over
these last 6 summers. I only average 3 - 4 captures a summer that
(I keep) as the greater majority of those which I encounter are
sadly worn or damaged enough --- that I leave them alone.

I will likely still be on the lookout for "diffrent ones" even after
completion of this 2nd drawer. These magnificent, large, and
intriguing butterflies certainly have a character all their own !

**Sharp-eyed enthusiasts will notice an over-sized example
collected by me in Mobile, Alabama (in the right corner). I
have to say that examples from the far south do seem to be
of larger proportions; as I saw others but, was unable to net them.

[Chuck]

The specimen from Mobile, AL is interesting.

A 2010 paper (Lehnert) on ssp maynardi determined that true maynardi is only found in southern FL, anything north of that is intergrade. The study was based on very advanced morphometrics, food plants, and more...but not genetics.

The size of your Mobile specimen is not unique amongst those found along the Gulf coast; they all seem to be large (i.e., maynardi sized). I wonder who might have done genetic analysis on Gulf populations to see if they are maynardi, nominate glaucus, or something else.

There is definitely a cline where the dark females stop abruptly; in MI it abuts canadensis and in NE it abuts MST. It has been stated (Scriber) that the further south one goes the more dark females there are, though I can say in NE KY about 75% of females are dark, which rather defies this.

Notably, both appalachiensis and canadensis have a rare dark female form; I'm unaware of a single dark MST female.

The variation in the amount of blue shown in your specimens is amazing, nice series to demonstrate that. ? Only one specimen (top right) shows a yellow (ish) "pistol grip" on the FW, I'm surprised your population doesn't exhibit that more often. Interesting.

[Trehopr1]

Here are a couple of those with the extra yellow markings on
the forewings that you mention chuck. Here they are VERY
pronounced; although typically they are not quite so bold.



These belong to a friend in Central Illinois. They are the best
of his 4 such examples. He has about as many as me but, most
(like mine) just seem to run the "typical" appearance.

[Chuck]

Interesting. Are those intergrade specimens from central IL as well as the owner? I would not expect them so far south.

[Trehopr1]

Yes they are Chuck.

They were collected in a field he is familiar with near his home which is less than an hour away from Springfield (the state capital).

[58chevy]

Here are a couple of female glaucus from the TX gulf coast. They are both very large. I assume they are not maynardi because they are not from Florida, but they closely resemble my maynardi specimens in size and appearance. I too would like to see a genetic comparison between glaucus & maynardi.

[Chuck]

Here are a couple of female glaucus from the TX gulf coast. They are both very large. I assume they are not maynardi because they are not from Florida, but they closely resemble my maynardi specimens in size and appearance. I too would like to see a genetic comparison between glaucus & maynardi.

That yellow female is distinctive with the deeply scalloped black on the HW between blue and yellow. I have nothing that comes close to that.

On another note, in maynardi the blue in the cells is separated by black veins, while glaucus the blue tends to flow more contiguously over the veins; from that perspective these appear to be nominate glaucus.

[joachim]

wow!!!!!!!!!!!!!

[boghaunter1]

Chuck says "Notably, both appalachiensis and canadensis have a rare dark female form". I would love to see a photo, more info, etc. on a dark fm female canadensis... that would be a real rarity IMHO.

John K.

[Chuck]

Chuck says "Notably, both appalachiensis and canadensis have a rare dark female form". I would love to see a photo, more info, etc. on a dark fm female canadensis... that would be a real rarity IMHO.

John K.

Perhaps @paulk or @eurtyides will chime in as they'd be more familiar. IIRC one was captured on Point Peninsula. I've heard reports of others, and I believe it's not just anecdotal, I remember reading about it.

Given that many animals have rare (or not) melanic aberrations, I wonder what the difference would be between an aberrant melanic Tiger and a "regular" dark female.

[Chuck]

That yellow female is distinctive with the deeply scalloped black on the HW between blue and yellow. I have nothing that comes close to that.

Hey, check this out! I did a look on iNat from Houston toward the east, and there's a whole bunch of yellow females that have the scalloping on the black. Here https://www.inaturalist.org/observation ... n_id=60551

[eurytides]

In Butterflies of Canada, they mention the rare all black female canadensis found in NFLD. They reference Morris but I have never read the original source of this info, nor have I ever seen pictures of this. This sounds more like an occasional mutant than a distinct colour form that you can consistently encounter.

I am not aware of any melanic MST. Chuck, would you care to elaborate?

[Chuck]

I am not aware of any melanic MST. Chuck, would you care to elaborate?

I have zero knowledge of a melanic MST. Never seen one, never read of one, never saw one in an institutional collection, never stumbled across a photo of one.

[eurytides]

Haha sorry Chuck, I misread your post. When you said you were unaware of a single dark MST, I misread that as “aware.” My bad.