A personal best for size.

[trehopr1]

Last weekend I hit upon a "golden" moment.
I went to a field which I've well known for years.
It also happens to be the farthest flung field I visit
within "reasonable" distance of my home. Reasonable meaning
an hour drive to our western counties bordering the Mississippi
river.

It is here, where I stand the greatest chance of encountering
North America's largest swallowtail species AND easily THE most
difficult species to encounter/find in our state. That species
being the Giant Swallowtail (Papilio cresphontes).

Of the 6 papilionid species present here in Illinois the Giant
has for me ALWAYS remained an enigma of sorts... When I have
encountered them I have found them only as singular individuals.
So, you better not miss! Seemingly, unlike all the other species
available to me I've never yet encountered a field hosting "several"
individuals at once.

In going to this haunt which I know harbors them "potentially"; I
risk a long drive to possibly find my favorite spot mowed for its
alfalfa/clover. It's happened before and I have not as yet discovered
any potential secondary sites nearby. So, I flip the coin and dash
there a couple times a summer with hopes...

Anyway, upon my arrival I was greeted by at least 4 yellow Tiger
swallowtails (Papilio glaucus) pollinating in the field -- which
was still uplifting. After investigating those one by one I took
pause to catch my breath and wipe my brow and whilst standing there
on a humid afternoon I scanned the field and something caught my eye
at distance to my far right.

I walking toward the object of my attention and realized I truly
had a P. cresphontes in my sights pollinating clover. I could see
it was a female as they are SO much browner than their male counter-
parts. With "baited" breath and a lump in my throat I stealthily
approached her half expecting her to take off in a heartbeat. These
can be flighty and nervous at times...

Well, with a bit of luck and a "gentle" sweep I secured this prize
of a species -- without knocking off a tail !

Here she is below, and she would be the only one encountered that visit.



However, the real "kicker" to this tale regards the size of
my newly captured "queen" of personal captures. To date,
my largest "personal best" for the species was an impressive
11.3cm wingspan specimen caught about 4 years back.

She on the other hand measure a full 11.7cm and is quite 
broad in wing area. A true best for size...

The species here, feeds on prickly ash which is much unlike
all those Floridian citrus loving examples.

I don't know if any of you have any personal bests (as well)
for this species but, I would welcome any pictures or honest
measurements (in centimeters) of any you may have from
anywhere within the Eastern U.S.

+The specimen should be spread perpendicular to the body
(like mine) for true comparison.

[exoticimports]

Ours are much smaller than those in FL.

I’ve only seen a few this year, odd given the mild winter.

Chuck

[lordpandarus]

I saw one in Montreal for the first time in my life this year, on top of the Mont Royal. It was flying I couldn't take a picture of it

[58chevy]

Nice specimen, trehopr. All the P. cresphontes I've caught in recent years have been smallish, ranging from 90mm to 105mm in wingspan as measured in mounted position like the one shown. I don't know whether the small size is due to agricultural chemicals, degradation of habitat, or whatever. I have some older specimens that are considerably larger but are poorly mounted and the forewings are at less than a 90 deg. angle to the body. This makes a direct size comparison to your specimen difficult. One such specimen, which I caught in 1963, measures 128mm wingtip to wingtip. Another specimen, from my uncle's 4-H collection, measures 137mm. I have pictures of the drawers they're in, but not closeups of the individual specimens. If anyone wants to see them, let me know here.

[Adam Cotton]

The best way to measure specimens to avoid inaccuracy due to spreading technique is to use forewing length, from base where the wing joins the thorax to the tip.

That way specimens can be measured however they are spread, or even if still papered.

Adam.

[trehopr1]

A question here Adam in the use of your measuring method.

It does not take into account the specimens body which could be
4-6mm in width as well.

Seems your method is like taking two forewings and your just
(in a manner of speaking) holding them together.

*Your just doubling the length of one forewing without
consideration for the body width.

Also, the manner in which you see my specimen spread has
LONG been a standard in the hobby.

I don't know why anyone would spread their leps any differently
(nowadays) unless it was for some stylized form of artwork.

I am aware that early British lepidopterists allowed their
specimens wings to "droop" somewhat making them less than
perpendicular to the body but, that was about 200 years ago.

Seems there is more room for inaccuracy with your method.

[exoticimports]

Adam is correct. It is the current method for measurements. Commercial specimens are measured across the tips to make the specimen appear larger.

Chuck

[trehopr1]

Hey 58chevy, have your ever considered a relax/re-mount
of either or both of those specimens ?

A matter of a few hours should soften enough to reset.

Anyway, I'm really just curious here as to how large this
species may honestly get when spread properly like mine.

I'm certain their are larger examples (likely out of florida)
but, just how much larger ?

I believe there are ones into the 12's and perhaps the 13 (something)
range (as spread) but, I've seen numbers in books and on the web of
14 to 19cm which is to me absolutely absurd !

So, this is why I'd like to see what others have encountered and
where collected (in the U.S.)

My largest P. glaucus maynardi (female) is a 12.3 so I figure there
has to be a P. cresphontes to match and exceed that...

[58chevy]

I agree with Adam & exoticimports that measuring the forewing length is the best size comparison method. It's the standard used in current literature. I'll go back & measure the forewing length of my specimens. If you'll do the same, trehopr, we can get a pretty accurate comparison. Hopefully other forum members will post measurements also. I have relaxed & re-spread specimens in the past, but not P. cresphontes. Maybe I'll get around to doing it. I have a black witch from my childhood that I purposely spread with the wings at less than a 90-deg. angle so that it would have a 7-inch wingspan. I later mounted it properly but the new measurement was only 6 inches.

[58chevy]

OK, I measured the forewing length of my 2 largest P. cresphontes (the ones that are poorly mounted). The smaller one (from N. central TX) measures 67mm. The larger one (from coastal Louisiana, captured in 1949) measures 72mm. Coastal LA has a very similar climate to Florida, so big butterflies should be expected there. P. glaucus maynardi, native to FL, might get bigger than cresphontes. Leroy had some huge specimens, but I don't remember him posting any measurements. P. multicaudata is sometimes referred to as N. America's largest butterfly, but I've never seen published measurements. I've heard P. appalachiensis gets big also.

[trehopr1]

Okay 58chevy, I laid my ruler down and measuring from the base of the wing (at the thorax) and angling the ruler to the furthest tip of the forewing I get a measurement of 74mm.

I not only double-checked my measurement; I went back a few minutes later for a third time for absolute certainty and that is what my number is on this particular butterfly.

[trehopr1]

I went back to my original maynardi thread as I do recall Leroy leaving some specific numbers on his two largest specimens.

He measured his largest dark example as well as his largest light example.

Here were his numbers using calipers and how they convert to centimeters:

Light form: 4.982 inches
= 12.65 cm.

Dark form: 4.790 inches
= 12.16 cm.

My largest example as mentioned before is 12.3 cm. so, Leroy's (light form) P. glaucus maynardi is yet slightly larger than mine at 12.6 cm.

That subspecies truly has some monsters present in those environs !

[58chevy]

There is also P.rumiko, the western form of cresphontes. I'm sure it is close to identical in size to cresphontes, since all the other physical characteristics are pretty much identical. Somewhere on the web there must be a list of measurements for the largest N. American butterfly species. As of now, I don't think there is a consensus as to which is biggest. P. thoas, another cresphontes look-a-like, occurs in the U.S. but I don't know if it breeds here.

[exoticimports]

I have a single rumiko for comparative studies, it’s small. So they do vary in size, would be interesting to know typical and max size.

Chuck

[mothman55]

My largest cresphontes measures 115 properly spread and 70 wing only. Reared a number over the years from south western Ontario larvae found on hop. One I reared last season and emerged this season has much more yellow in the wing tips that usual. I will post a pic later.