ilex?

[Paul]

Could I ask for opinions regarding these two different individuals?

[Padfield]

Hi, Paul, me again!

The first picture is pretty unambiguously false ilex. HOWEVER, the second one has me umming and aahing.

For false ilex, it has the following characteristics:
Ground colour
Distinct reddish tinge to orange spots
Apparently flat hairstreak at anal angle (difficult to see in s1a)
No hint of white marginal line in s6

For ilex, it has the following characteristics:
Obvious black edging to spots
Pronounced white marginal line (in my pictures this line remains at least vestigial in s6, though - no idea if this is significant!)
White internal edging to the submarginal spots
Hairstreak continued onto forewing

I incline towards false ilex for this one too, though I won't be put out if someone else disagrees.
The black edging is indistinct, even though it is quite extensive.
The hairstreak on the forewing is very broken. In my experience, even when this line is very weak or vestigial in ilex hairstreak the markings are quite long and give the impression of being almost continuous.
The ilex hairstreaks just to the west of you, in the Val, are all very strongly marked and quite different in general appearance from yours. This last is not a strong argument, because travelling a few hundred kilometres through mountains is probably equivalent to a much longer journey in the lowlands and the populations are probably effectively isolated.

My other reason for inclining towards false ilex is that you have photographed a lot of individuals and both Tim and I have placed all the others as false ilex. Where it occurs, ilex is generally common and it seems more probable that a single butterfly looking rather like ilex is the extreme of false ilex variation rather than an isolated ilex hairstreak among all the false ilex.

I do hope someone disagrees with me!! My own view is that one should be conservative and where there is doubt go for the known, or commoner species. Life ticks are so much more exciting when you know they really are life ticks and from the scientific point of view records should be definitive not optimistic.

Here's to hoping...

Guy

[Padfield]

Here's that weakly marked ilicis annotated to draw attention to some of the points.

I still hope I'm wrong...



Guy

[Paul]

Guy.. thanks very much yet again.. I've a lot to learn!!!

[Roger Gibbons]

For me, the colour of the red marks is constant and definitive even when the other clues may be inconclusive. I credit Tim for realising this. I’ve added two photos (11003 and 11072) from June this year which I think show this clearly.

satyrium ilicis_11003.JPG (156.48 KiB) Viewed 623 times

satyrium esculi_11072.JPG (186.01 KiB) Viewed 622 times

I agree with Guy’s analysis. I would add that the red marks in False Ilex can sometimes be quite thin, as in your photo 1, but the thicker marks in photo 2 don’t necessarily indicate Ilex. The False Ilex marks can sometimes have a light black external edging especially in s2. The hairstreak in Ilex is often quite irregular and broken. In False Ilex the hairstreak can extend to the fw but if it does, it is not strong. A strong fw hairstreak confirms Ilex. Your photo 2 has some distinctly Ilex-type features, but on balance I feel it must be False Ilex. So often the so-called ID characteristics cited in the books are not conclusive; someone ought to write the ID books that lists these features with the percentage probability of positive ID in each case.

On my site, I’ve put these two species alongside each for comparison. I have better photos from 2008 that I’ll add later this year.
http://www.butterfliesoffrance.com/html ... ilicis.htm

I’m guessing that your photos were taken in very southerly locations as they seem to be all False Ilex. And I’m guessing that you’re keen to see Ilex as per the references to life-ticks. It’s quite common and I’m sure you’ll meet it soon. False Ilex seems to occur, sometimes in vast numbers, in hot scrubby areas, whereas Ilex seems to avoid these and go for areas with more vegetation. I have seen False Ilex in thousands where there were no other hairstreaks at all, as far as I could see.

If you’re in Var next June, I can show you places where you can see Ilex, False Ilex, Sloe and Blue Spot (and maybe even the less common White-letter) in substantial numbers.

[Paul]

Once again, many thanks, & hope I may be able to take you up on that one day!!