Festoons

[CFB]

Yesterday, in the Alpes-Maritimes, I saw my first Southern Festoon:

I assume that the lack of blue and red spots on the hind-wings is due to age. This morning I went back to see if there were any more there, but there weren't. However a few hundred metres away I found a Spanish Festoon

which I discreetly followed. It happened to find a member of the opposite sex, and I had plenty of time to take a lot of photos, one of which is:

They were still at it when I had to leave them, as I didn't want to be late for lunch.

Amongst other butterflies that I saw was a Small Heath,

and a Glanville Fritillary:

I also saw this caterpillar. Can anyone identify it for me?

--
Colin

[Padfield]

Hi Colin.

Your southern festoon looks to me like a worn Spanish festoon. I've never actually seen a southern festoon, so this is more of a query than a contradiction, but my instinct just says 'Spanish' to me. Spanish festoon readily loses its red on the forewing, as in this individual photographed in Spain last year:



Don't hesitate to tell me I'm wrong - I'm merely interested!

Guy

[Padfield]

PS - Your cat is either M. deione or M. athalia, I think - and I would tend towards deione. Again, no authority claimed or implied!!

Guy

[CFB]

Guy,
I thought that it was a Southern Festoon based on the very wavy black submarginal lines on the hind-wing, which are better shown on this photo:

Also the pattern at the front of the fore-wing looks very different from this, very worn, Spanish Festoon:

So I don't know Let's see if anyone else has any good ideas
--
Colin

[Roger Gibbons]

I rather suspect Colin has got them right. When these two species are fresh they are fairly easy to tell apart, but it is entirely a different matter when they are worn. I think that maybe the key is the marks in the forewing cell – when Spanish (rumina) is worn the marks that held the red become “empty” whereas for Southern (polyxena) they were never red and remain solid black.

Here are a couple of photos of rumina that illustrate this: 28787 was taken on 21 April and 29077 taken today. I think they are of the same butterfly, showing how wear affects them over a two week period.

[Padfield]

2:1 against so I concede. But I am very surprised, as I can still only see Spanish festoon there - and I was even more convinced after Colin posted the next photo as it reveals residual red in the appropriate places. In Spain, individuals showing little or no red do not show 'voids' instead (as in my photo above).

I'll get out of your diary now, Colin!

Guy

[Reverdin]

Looks like this one from last year, I have dubbed Southern....

but in the first shot.. there DO seem to be red patches, or is it a trick of the worn appearance... anyone for a hybrid?

[Roger Gibbons]

I think yours is definitely Southern/polyxena, Reverdin. Interesting red spot – why did these red scales survive and the others not? I don’t have any photos that show this part of the hindwing so cannot say whether this is normal. The Lafranchis ID book shows this red mark, so clearly it is.

If I saw Guy’s Spanish/rumina (as seen in Spain) down here in Var, I would have considered this to be strong evidence of a hybrid, but this cannot be so because polyxena does not occur in Spain. I have checked all of my rumina photos and they all conform to the same basic pattern. The Lafranchis ID book specifically cites the red forewing costal marks as being “proof” of rumina (and goes so far as to say that the absence of them is “proof” of polyxena). This rather leads to the conclusion that Guy’s rumina is the odd one out – were they all like this in Spain, Guy? Makes a bit of a mockery of Lafranchis’ guidance if they were. One would expect the Spanish population to be the “type”.

On a general question, do some scales wear more readily than others? It is clearly so for the Festoons, but Camberwell Beauties have yellow borders before hibernation and white ones after, but the rest of the butterfly seems unchanged (apart from the battering of hibernation). Also in April in Var, male Cleopatras appear to have lost their orange upperside forewing scales, and I am rather assuming this is a result of hibernation. Many appear Brimstone-like in flight but when settled, the wing shape looks decidedly Cleopatra-like. Brimstone does not occur in the far south of Var (at least I don’t believe it does, despite the distribution shown in Lafranchis), so this maybe adds more evidence to the fact that they are yellow Cleopatras.

[Padfield]

Rev's is undoubtedly polyxena - that is instant, unproblematic ID. The red on the hindwing is standard.

Tim Cowles is confident, like you both, that Colin's is polyxena but I still can't see it. If everyone apart from me is correct (which I guess I have to accept), then what intrigues me most are the red scales on the forewing of Colin's insect in the cell spot (on both sides) and in s.4. I have never seen a picture of polyxena with any red there at all. There is no doubt this insect had red there.



Spanish festoon frequently has just a few red scales like this rather than full red spots.

The nature of the undulations on the forewing margin of Colin's seem quite wrong for polyxena to me and the shape of the brand in the hindwing cell is sort of intermediate between the two.

On the other hand, the isolation of the red spots on ther hindwing does point to polyxena.

I'm quite intrigued.

Guy

[Padfield]

I didn't get where I am today without being persistent, even when wrong - so I persist.

Natural hybrids of polyxena and rumina are scarce but at least 5 are known and matings between the species are seen relatively frequently. Hybrids are readily produced in the laboratory.

I have reason to believe this individual may be such a rare hybrid.

Looking for features to back up my intuition that this cannot be polyxena, I have settled on the pink spot in s.4 - the lower of the two indicated with a question mark in this copy of Colin's insect:



This spot is not present, pink or white, on any photo of polyxena I can find using Google images. The upper one is present, as a red spot, on a certain percentage of polyxena but the lower one is invariably absent - there is nothing in that gap. To locate the pertinent spots on a photo, count pale bands along the costa and look in the dark between bands 5 and 6.

Both these spots are, however, typically present in rumina, though sometimes merely as red scales.

Similarly, red scales in the dark cell patches are standard in rumina and entirely absent from polyxena - yet Colin's insect has them.

Coupled with the anomalous forewing marginal markings (which are instantly recognisable in polyxena) these spots probably explain my intuition.

HOWEVER, the hindwing seems intermediate between the two species, in ways we have already discussed.

If Colin had a picture with the light coming through the wings the absence (or presence) of the vitreous spot in the forewing would be useful but this is rarely visible in flat upperside pictures, especially when worn.

It seems cheap and easy to go for the hybrid option but I do find this individual highly anomalous.

Guy

[CFB]

Guy,

I'm afraid I don't have any photos with the light coming through the wings.

I did however notice that the first photo in Species-Specific Albums - Southern Festoon - Imago by NickB seems to have red in the cell spot:

gallery/image.php?album_id=822&image_id=11090

I tried to insert the photo here in the text, but failed miserably
--
Colin

[Padfield]

Well spotted - that's one brick in my wall down!

But there's no hint of that spot in s.4. I'd be fascinated if anyone could find a southern festoon showing that spot...

EDIT: I've just noticed the spot's in s.5! I didn't count - just saw it coming off the end of the cell and called it 4.

Guy

PS - Although I'm a teacher I was called to the Bar in 1995, in the Inner Temple. The adversarial approach to truth is in my blood.

[CFB]

How about this one, particularly on the right wing:

http://www.galerie-insecte.org/galerie/ ... 0_026s.jpg

--
Colin

[Padfield]

No - the spot is missing on both wings, though that individual does show red scales.

That butterfly is also unambiguously southern festoon - I wouldn't doubt it even if it had red spots.

I really do accept I'm probably wrong - but the possibility of a hybrid is fascinating and I won't let this drop too quickly... Doubtless I'll emerge wiser.

Guy

[Reverdin]

Now this is really interesting. .. I think this is the same butterfly as Nick's... but it doesn't show much red!!!... so is the angle imperative??
I still support the hybrid theory

[CFB]

This afternoon I went back to the site where I saw the butterfly that is the first photo in the first post in this topic. Once again I saw only one Festoon, which was busy chasing, or being chased by other species, in particular Owlflies, some blues and a few fritillaries. After quite a long time, it settled, enabling me to photograph its underside:

Then there was more chasing, but after a couple of minutes it settled again for quite a long time:

Do these photos make it any clearer as to whether they are Spanish Festoons, Southern Festoons or hybrids?
--
Colin

[Padfield]

I continue to find this fascinating. Although I suspect Roger and others will see this as even more certainly polyxena(!), it still shows features quite out of character with that species. The submarginal region of the underside hindwing is a case in point. All Roger's excellent pictures (http://www.butterfliesoffrance.com/html ... lyxena.htm) show a narrow, zig-zag, reddish line, bordered in black, with very pointed spots inside this line. In fact, all other pictures I can lay my hands on show this, but Roger's are the best piccies . Colin's latest butterfly has broad, yellow arches and the spots and crescents are all very rounded - much more like rumina. It has hints of the upperside spots on the forewing I noted above, but only hints.

I guess the most likely answer is that this is a local population of polyxena that differs from other populations. But I would strongly entertain the possibility that there has been mixing of genes at some stage, perhaps some generations back. Colin's butterflies shatter my preconceptions about what polyxena should look like (polyxena is probably the commonest butterfly I've never seen).

There are several references to hybridisation in the literature - and Lafranchis (in his first, French, book) mentions both a coupling and a hybrid. But the only illustration I can find of such a hybrid shows an insect with considerable red on the forewing, very like rumina. I can't link directly to the pdf showing this insect but if you copy and paste "Diane Proserpine Aristoloches Synthèse de l'enquête Année 2006" into Google you'll find it.

Guy

[CFB]

Hello Guy,

Your reference to "Diane Proserpine Aristoloches Synthèse de l'enquête Année 2006" led me, via its Bibliography, indirectly to http://www.onem-france.org/diane/wakka. ... erynthiaId, a very interesting page which itself contains many additional links.
--
Thanks,
Colin