"Spring Tigers" in northern Illinois

[Trehopr1]

Here in the northern portion of Illinois the sighting of
our (1st brood/spring) Tiger Swallowtails (P. glaucus) is
a rather rare or infrequent occasion -- at best in the
vast expanse of "suburbia" beyond the Chicago city
limits. Suburbia (here) stretches west & southwest for
some 60 miles before rural Illinois starts taking shape.

Lake Michigan seems to play the "devils advocate" much
of our winter AND spring with what has been termed
"lake-effect" weather often mentioned on the news
channels. This sorted weather is both good and bad in
either season (depending on how the wind blows) and
in what storms hit us head-on from the west, south, or
north. Couple this with an already "tamed" environment
where wild spaces/places are fewer by the year and you
have a ripe situation for hardly ever seeing some things
even when you are a naturalist/lepidopterist.

Spring here typically "starts" 2nd or 3rd week of April with
the grasses greening-up and trees budding by months end.
Flowering trees mostly run the coarse of May but, are done
by 1st week of June. My earliest personal sighting of a
"spring tiger" occured in (2001) on May 6th. All others have
arrived at or around May 15th (according to my tracking
records). On average, I only make 2-3 sightings in any given
springtime.

Here is a photograph of the diminutive spring tiger brood
of which this discussion is about.



The average wing-expanse of these little fellows is typically
about 3 to 3 (1/2) inches. I have looked for them on lilac bushes
yet, never seen a one.... Have trolled several fields over the
years with budding clover to still --- never see a one. However,
I have found they strangely seem to have a fondness for wild
phlox flowers which are not easy to find anymore here (except
near woods/forest preserves). The occasional homeowner may
have some as pretty garden flowers !

Spring tigers (as a brood) don't last very long. Our un-stable
weather conditions during May which are exacerbated by our
"lake effect" AND struggling food sources seems to very much
limit sightings to singular lone individuals on the wing.

In summary, in all my life in this region I have probably seen/
encountered no more than 20 or so over the years. Some years
our spring is "pushed-back" due to inclement weather conditions
with "spring tigers" stiil emerging and present the 1st and 2nd
weeks of June.

This VERY LATE capture was made on June 17th 1988.

I'm certain that one could fair much better at encountering this
1st brood if you lived more rural or at least had MORE wild
spaces available.

But, where humanity reigns supreme and the environment has
been "tamed" such fragile visitors as these are only a "passing
shadow" in the overall picture of things....

[Chuck]

Enigmatic indeed. As we now know, the "Eastern Tiger Swallowtail" common throughout the northeast USA, is not. We're working on the description of the Mid Summer Tiger Swallowtail as Papilio iroquoisus.

Given that, with canadensis and iroquoisus both being univoltine, the question begs: what is Spring Form? Though often cited as looking like canadensis, the verso HW lunules typically resemble those of glaucus, not canadensis. COI would go a long way to determining what Spring Form is, and there are probably some in BOLD, but trying to locate them manually is a chore.

In our town, Spring Form flies though that may be drastically reduced, with the town population jumping from 8,000 to 25,000 in less than ten years, as people in the neighboring urban/ suburban county flee the dystopia they've created. Thus, we're leaving before the town is totally wrecked, built up, and spoiled.

In the Finger Lakes region of NY, Spring Form can be most easily found on Lilac WHEN the flight and the bloom coincide, which is a bit less than 1/3 of years. Other than that, on those rare occasions they do alight, it's on the ground.

On taxonomic determination, Spring Form is readily misidentified. I've seen "Spring Form" in institutional collections that are, in fact, canadensis or iroquoisus. Sometimes the date should (have been) a dead give-away. In Finger Lakes, Spring Form appears in the last week or so of May; IIRC the latest specimen I have is 09 June. Of course, the flight period will vary extensively by location & environment.

[Trehopr1]

I have adjusted the title of my post Chuck.

[adamcotton]

I don't think it is a good idea to use the yet to be published scientific name for what I assume has previously been called 'MST' here. Once it has been validly published there will be no issue about using it, but if the name appears even on a forum like Insectnet it will spread and that could become problematic.

Adam.

[Chuck]

Treehopr, they surely are enigmatic, so you were correct in your original title.

An old paper, much has been learned since then- but I'm unaware of any recent studies that examine it in more detail.


1990 THE GREAT LAKES ENTOMOLOGIST 127

INTERACTION OF INTROGRESSION FROM PAPILIO GLAUCUS CANADENSIS AND DIAPAUSE IN PRODUCING "SPRING FORM" EASTERN TIGER SWALLOWTAIL
BUTTERFLIES, P. GLA UCUS (LEPIDOPTERA: PALILIONIDAE)

J. Mark Scriber

[papiliotheona]

Most multivoltine U.S. papilionids feature the first flight of the year smaller and more delicate than subsequent broods.