Intraspecific variation pyrgus serratulae

[Bert-Jan Luijendijk]

Hi all,

During the past 3 years I have spent together with my family some holidays in the south eastern part of France. During spring (late April or early May) I visited the Vaucluse and during summer I visited the Ubaye region of the French alps.

Studying the variation in pyrgus species is there one of my favorite activities. I try(!) to record the upper and underwing of practically every specimen I encounter. Much has already been written about the identification of pyrgus species and you can often get by with it, at least when it comes to the distinct specimens of a certain species. A species for which I think this applies to a lessser extent, especially with regard to the upperwings, is serratulae. Below are two examples of what I believe are serratulae, with striking pale markings on the upper fore and hind wings, which in some cases even evoke associations with carthami. This phenomenon did not seem to be rare, as I encountered it regularly. Does anyone knwo whether this feature characteristic for serratulae from this region?

Thanks and kind regards, Bert-Jan Luijendijk

[Roger Gibbons]

Good question, Bert-Jan!

This is clearly carthami on the upperside and serratulae on the underside, if nature should permit that to be possible.

This is one of those individuals that just does not fit the accepted ID features. There are very good reasons why it cannot be either of them but it has to be something (to state the obvious). My feeling is that there are less reasons to preclude carthami than serratulae, so if the balance has to go one way, my vote is for carthami on the simple basis that the upperside screams carthami and almost certainly not serratulae. I agree that serratulae can be more strongly marked (than the books usually show) on the upperside forewing, but not so on the hindwing and the marginal dashes are definitely carthami and not serratulae. This is more on the balance of probabilities rather than beyond any reasonable doubt.

The carthami underside is usually made clear by the white marginal band (but sometimes serratulae can have this) but this can be less distinct as in this shot from the north of the Alpes-Maritimes:
https://www.butterfliesoffrance.com/htm ... es_2Jul12_

The date does not rule out either as both can be on the wing fairly early, and both fly at altitude.

Roger

[Bert-Jan Luijendijk]

Thanks a lot for your feedback, Roger! Good to see, that you have choosen the other side .

Regarding the pyrgus from Jausiers, I should add that it flew at 2500m altitude and was noticeably tiny, as even the photo suggests. I can't recall the latter however from the Monieux specimen. I didn't expect however that carthami would already fly during the first days of May.

I can fully understand your remarks concerning the upper hindwing markings, but I still feel that these markings are somehow not typically shaped for carthami, as I would in that case rather expect more regular spaced, sharply demarcated and spiky submarginal spots (like in sidae).

Few weeks ago I was again in the Vaucluse. Besides the abundant onopordi and less abundant malvoides (and some sidae in the Var), I only saw the following pyrgus (2 of them, which I barely could separate individually) - again on the Vaucluse plateau. Concerning their identity, I was, until this evening, leaning towards serratulae, but I guess you would call it carthami too?

Cheers, Bert-Jan

Edit: I discovered that I had photographed both individuals of last visit and that I had attached to my initial post the underside of individual A and the upperside of individual B. I have corrected this by adding the photographs of both individuals. Picture 1-2 are of individual B and pictures 3-5 of individual A - both photographed at the same date 8 May at the same location (Vaucluse plateau).

[Padfield]

Hi. For what it's worth, I have no doubt this is serratulae. I have found the same extreme phenomenon twice now, once in the Rhône Valley, where both species fly, and once high up in the Pré-Alpes Vaudoises, where there are no carthami. Less striking forms are common.

Here are some shots of the Rhône Valley serratulae (May 21st, 2016):





The files are named 'carthamiserratulae21may2016x.jpg' because at the time I was simply baffled. But I quickly came down on the side of serratulae.

Here is carthami from the same day, and the same place:



Guy

[Roger Gibbons]

Looks like the underside trumps the upperside! I think this re-writes the rule-book on the range of the strength of markings for serratulae.

The unh marks (especially basal s7, discal s1, discal s4/5, marginal s2) looked exactly right for serratulae, just the upperside that created any doubt. The markings on both surfaces can be quite variable for many Pyrgus but the unh is less prone to variation and maybe should be trusted more.

I don’t have any books with me but I strongly suspect that most, if not all, state that the upf marks are small and the uph largely unmarked.

I see a lot of serratulae in the French Alpes - nearly always in July - where it is widespread and often common, and I have never seen any with the strength of uph markings of Bert-Jan’s or Guy’s. This is the nearest I have seen to the uph markings:

The only rationale I can think of is that these early season examples have heavier markings than later broods, as seen for other species such as sinapis, etc.

Roger

[Bert-Jan Luijendijk]

Hi Roger,

I've got some books with me. To cite a few sources:
- Jacquier, Éléments d'identification des Pyrgus de France métropolitaine (2017): "pale spots weakly marked" [translated from French]
- Lafranchis, Dagvlinders van Europa (2009): "uph without obvious pale markings" [translated from Dutch]
- Lafranchis, Papillons de France (2021, pdf) : "pale spots, often faintly marked, on the hindwing" [translated from French]
- Raymond & Gibbons (EBG, 202?): "pale, weak, often completely unmarked"
- Tolman, Collins Butterfly Guide (2008): "Uph markings obscure"

Looking through the photographs of serratulae at the website of Wolfgang Wagner (http://www.pyrgus.de/Pyrgus_serratulae.html, I do however see several individuals with more obvious markings at the uph. Most photographs were taken in the southern part of Germany and some from Greece. Also on the website of Philippe Bricaire https://www.fleetingwonders.com/pyrgus-serratulae.php are several specimens visible with clearly marked uph, even from the French Alps, with - by coincidence? - the most striking individuals coming from the lowlands of the Provence (#49-#52, #58-59).

In just about a month, I will be two weeks on holiday in the southern part of the French Alps (Ubaye) and I am curious what a systematic sample on (photographed) uph patterns of serratulae will reveal - provided that there are sufficient numbers on the wing (like 2023, but unlike 2022). Sampling serratulae in the lower parts of the Provence will be much more difficult I guess, as they seem to be quite scarce in that region.

Kind regards, Bert-Jan