Melanic Papilio canadensis
gatrelle at tils-ttr.org
Thu May 17 00:02:27 EDT 2001
I'm a southern US come-lately to this situation , but I'm picking up on the
nuances quickly. What is the situation? 1) That incorrect assumption has
played a large role in the morphological taxonomy of eastern NA Tiger
Swallowtails for a long time. And, 2) that genetics alone is at times a
"blind man's" taxonomy - it is absent of every factor found in nature.
Where things stand now, there is definitely a "second" species of Tiger in
the Appalachian mtns., and this same undescribed is a third species in the
northeastern US and southeastern Canada. We learned some years ago that
canadensis was not a subspecies of glaucus. I predict that what the
"geneticists" have apparently called a hybrid glaucus X canadensis is in
nature a good species. A lot can be learned in the lab - stuff that can't
be learned from what is in the field. But the reverse is all too true too.
I have seen with my own eyes the differences in phenotype, flight pattern,
overlapping broods, size, etc. to know that no matter how close the genetic
information - the insects in nature "know" they are two species.
Evolutionally it makes sense that these species evolved in the "south". A
possible proof of this is the seeming chaotic array of female forms in N.
GA, W. SC, and W. NC. This now makes sense, if understood from the
perspective that this "area" is where the species separated and developed
the yellow only females of the undescribed and the yellow or black of
glaucus. Genetically, there is still a lot of dimorphic flux (instibility)
in this region. Why should we only expect several species of Tigers in the
West? Why not the East too? And what if this undescribed in not from a
glaucus ancestor at all but is the current entity from some long past
connection to rutulus? It looks very much like it.
So what of the "black" females in Newfoundland? Are they really canadnesis?
are they a genetic reversion to a past genetic link to glaucus dimorphism?
Does the univoltine undescribed also have black females - I've never seen
one. It is obvious that one of the things that is now occurring is that we
are finding there are perhaps a lot of cryptic species out there in eastern
NA. A lot of taxa need a second and third assessment. Simple watching may
get a lot more complicated as visible human delineations are dissolved with
the discovery of new cryptic species. This also means that there is still a
lot of collecting that needs to be done even in the eastern US to gather
samples for closer, and broader, taxonomic study.
PS One of the most interesting things I have ever seen was just a few days
ago. One of the large undescribed Tigers was intent on "driving" the
smaller glaucus males from a puddling area. This was not the typical male
chasing male partner searching that we see all the time. Twice I saw this
male actually drive the glaucus to the ground and bully them. One glaucus
was only half the size of the undescribed and almost immediately dove into
the grass and "played dead". It did not "attack" the other undescribed
males. At all the other puddles the two species looked to get along fine.
----- Original Message -----
From: "gwang" <gwang at mb.sympatico.ca>
To: <leps-l at lists.yale.edu>
Sent: Wednesday, May 16, 2001 7:43 PM
Subject: Melanic Papilio canadensis
> Hi y'all,
> In The Butterflies of Canada by Layberry et al., it is stated that
> "Another distinctive difference is that the Canadian Tiger Swallowtail
> does not have the black female form that occurs in glaucus. Oddly
> enough, the only exceptions to this rule are the occasional all-black
> females that have appeared in Newfoundland, despite the fact that they
> do not appear in New England." (pages 87-88)
> Any thoughts on why melanic P. canadensis are restricted to
> Newfoundland, and what this might mean with respect to the genetics of
> this species?
> Xi Wang
> Winnipeg, MB, Canada
> P.S. V. atalanta, and V. cardui are quite abundant here as well.
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