Beautiful Ab. P. canadensis

[boghaunter1]

Hello Everyone... Happy early Summer!

This year, the lilacs really put on an impressive show in late May - early June. I spent a week (4-6 hrs. each afternoon) sitting in a lawn chair with my newly acquired close focus binoculars & naturally, of course, haha, my net. As an aside, I would highly recommend these binoculars, Pentax - "Papilio II" - 6.5X x 21... they are small, light weight, have a crystal clear image & can focus down to only 18"... & were, to boot, very reasonably sale priced... around $125.00 CAD @ Amazon. I continually scanned the lilac blossoms every day & was finally rewarded, late on 30th May, @ 6:00 pm, with the collection of a stunning aberration of our common Canadian Tiger Swallowtail, Papilio canadensis pictured below

In the distant past I've had the good fortune to collect 2 other interesting abs. of P. canadensis... ab. "fletcheri" which is familiar to long time members/viewers of insectnet.com & the unusual ab. pictured in my avatar... ab. "radianthus"?

The next day, 1st of June, on the same lilac bushes, I collected a perfect, freshly emerged, male Black Swallowtail (P. polyxenes asterius)... only the 3rd ever collected in my area. I can post photos later, if wanted, of this latest P. canadensis ab., as it is still on the spreading board ... I leave all my lepidoptera specimens on the boards for a month, minimum, to ensure complete dry down with no drooping.

John K.


[attachment=2]Ab. Tiger S-tail 30 May 2025 - III.jpg[/attachme

[Chuck]

That is spectacular.

I wonder if this relatively common morph in your area is environmental or genetic? Perlman & Perlman demonstrated form fletcheri and others to be environmentally induced; Scriber wrote that such genetic changes are inheritable. I wonder if your "fletcheri" produce more fletcheri.

[wollastoni]

Wonderful form congrats !

I thought the fletcheri-like forms were temperature triggered ab so I don't really understand how it can be inheritable. If you can share the paper Chuck, I would be interested to read it.

[adamcotton]

Melanism like this can be caused by a sudden sharp cooling of the still soft pupa within a few hours of the pre-pupal skin being shed. Note that once the pupa has hardened completely cooling has absolutely no effect. This is absolutely environmental, but it is also possible that similar aberrations can have a genetic basis.

It is quite possible that such sudden drops in temperature could be quite common in the canadensis habitat(s) that boghaunter1 frequents.

Adam.

[boghaunter1]

Hello again,

A little back story to the weather/temps prior to netting this unusual Swallowtail. The month of May in Sask., as well as here in N.E. SK., was very cold & very dry, with drought conditions resulting in huge forest fires in northern SK... one fire N.W. of my location burned 1,125,000 acres (450,000 hectares)! Saskatchewan is a huge province... larger than Texas in area. May was also interspersed with short (1-2 days) & longer periods (every day for the last 9 days of the month) of abnormally hot daytime temps.

On May 30th, when I first caught this aberrant butterfly, the daytime temp. peaked at 33 C = 92 F & was the hottest day of the month. The previous 8 days (22-29 May) saw consistent high temperatures ranging from 24-31 C = 75-89 F. Mid May (13-21st) saw some very cold daytime temps (15 May daytime high of only 7 C = 45 F!)... the rest of the days, during that same time span, never broke 15 C = 59 F. As well, we experienced 3 nights of light frost (-1 to -2 C = 30 to 28 F) from 16-18 May. During the first week of May, we set a daytime record of 32 C = 90 F. on the 4th... I have personally, never experienced such a high temp. so early in the season. May 12th peaked at 29 C = 84 F.

To conclude... during the month prior to the eclosion of this unique Swallowtail, & at a time when the butterfly would have been developing within it's chrysalis, it was continuously subjected to a host of extreme alternating temperature highs & lows. These sudden temperature shifts could certainly be responsible for this extreme aberration. Anyone else collected any similar specimens (besides the regular marked fletcheri fm.)? As wollastoni said, this appears to be a fletcheri-like weather induced variation. It is interesting to note that during that week of butterfly watching, at the lilacs, I observed several hundred+ individual P. canadensis... all with completely "normal" tiger markings... except for one! I would also like to read the paper Chuck mentioned...

Also note that there is a roughly circular hole in this butterflies upper left wing... something I have observed before in other aberrant butterflies & was probably caused by desiccation & ensuing difficulties in expanding it's wings in the hot, dry weather. However, other than that imperfection, I am still amazed at how fresh & how vibrant the colors & patterns are on this specimen. Additional photos, when off the spreading board, in the next week or two.

Suffice it to say, I will be back in my lawn chair scanning the lilacs every spring, watching to see if any additional stunning aberrants show up!

John K.

[adamcotton]

To conclude... during the month prior to the eclosion of this unique Swallowtail, & at a time when the butterfly would have been developing within it's chrysalis, it was continuously subjected to a host of extreme alternating temperature highs & lows. These sudden temperature shifts could certainly be responsible for this extreme aberration.

The sudden cooling would have happened when the pupa formed BEFORE diapause, i.e. the previous year. As I mentioned before, temperature fluctuations have no effect on fully formed pupae.

Also note that there is a roughly circular hole in this butterflies upper left wing... something I have observed before in other aberrant butterflies & was probably caused by desiccation & ensuing difficulties in expanding it's wings in the hot, dry weather.

This hole in the wing was caused by a 'blister' forming in the wing membrane as the pupa starts to develop. After hatching, the butterfly expands its wings and while drying the blister bursts and the wing membrane over the blister breaks into small pieces as it dries, leaving this round hole in the wing. Such blisters can form in any butterfly wing, and are not related to the aberration.

Adam.

[boghaunter1]

Thank you very much Adam Cotton for your expertise in explaining the probable cause of this aberration & the "hole" in the forewing. Your knowledge of the Swallowtails is incredible.

John K.

[Paul K]

Your canadensis is out of this world !!!
And what are the odds that such unique specimen has had developed a „blister” ?!

Congrats

[kevinkk]

Super! The explanation of the process is interesting, I know it's come up before, so apparently these type of abberations would be more common in areas with more dramatic weather changes than more even climates.

[boghaunter1]

Hello again,

Thank you very much to everyone for your positive compliments on the recent LUCKY collection of this rare aberration. I wish that same luck would help in winning a lottery!..

By the way... in my area, the summer of 2024, was also a very hot, dry season with drought-like conditions interspersed with brief cooler temps & heavy sporadic rain showers. Remember, last year, all the smoke from massive forest fires in W. Canada drifting far S. into the USA, causing breathing problems for millions! When the larva of this aberrant would have pupated in July-August '24, temps, for many days, reached well above 30 C = 86 F, with a number of days exceeding 34 C = 94 F... certainly favorable environmental conditions that may have contributed to the '25 production of this interesting aberration (as outlined by Adam Cotton above).

John K.