Reverdin's, Idas or Silver-studded Blue (1 Viewer)

[balkantrek]

Excuse the quality of the photo, but my young son caught a Plebejus sp. in his bug pot and presented it to me for identification. It comes from Bulgaria's Rodopi mountains and there are three possibilities: Reverdin's Blue, Idas Blue and Silver-studded Blue.

My personal feeling is that this is Reverdin's Blue.

I started by ruling out Silver-studded Blue for a couple of reasons:
1. The orange band on the forewing is bright and long, reaching right up to the apex. On Silver-studded the orange tends to fade away towards the apex.
2. The orange band on the hindwing is thick and solid, the orange lunules fusing into each other. On Silver-studded the orange lunules tend to be distinctly separate and only just touching.

Deciding between Reverdin's Blue and Idas Blue then posed the next problem.
I decided to go for Reverdin' rather than Idas because the black lunules on the hindwing tend to be sharp arrow-like chevrons < in Idas Blue, while they are more gently rounded c in Reverdin's.

I would welcome any other opinions. These Plebejus sp. are notoriously tricky.

 

[Davebutterflyman]

Your breakdown on reaching the conclusion of Reverdin's Blue is spot on as far as i can see Balkantrek and i would have gone on those two points as well.

My experience with P.idas is that the black lunules are generally more angular in northern populations,Switzerland is one place for example,and i have noticed in some SE populations in Greece that more individuals are less angular but still not as rounded as P.argyrognomon so some populations would seem to show geographical differences.

That could potentially make separating P.idas from P.argyrognomon tricky but i would go with Reverdin's on the make-up of the black lunules and the broad continuation of the orange band.

It's a very tough one to attempt in the field and nigh on impossible at times i would say for a definiative id.....thank goodness for cameras!!

 

[balkantrek]

Your breakdown on reaching the conclusion of Reverdin's Blue is spot on as far as i can see Balkantrek and i would have gone on those two points as well.

My experience with P.idas is that the black lunules are generally more angular in northern populations,Switzerland is one place for example,and i have noticed in some SE populations in Greece that more individuals are less angular but still not as rounded as P.argyrognomon so some populations would seem to show geographical differences.

That could potentially make separating P.idas from P.argyrognomon tricky but i would go with Reverdin's on the make-up of the black lunules and the broad continuation of the orange band.

It's a very tough one to attempt in the field and nigh on impossible at times i would say for a definiative id.....thank goodness for cameras!!

Thanks for your comments and a second opinion.

I totally agree about what a wonderful and important aid cameras, particularly digital, have been for butterfly identification. They are playing a really important role in aiding identification and thus more accurate knowledge of species distribution.

 

[Jos Stratford]

I agree.

 

[Gavia_immer]

Just with that picture I cannot be 100% sure it is Reverdin's, but certainly I would say it is the most likely to be. Great finding of your son, Balkantrek! :t:

 

[balkantrek]

Glad to see you are still about Gavia, and thanks for popping onto the thread and adding your input.

My little son is only 7 years old but has already added a number of interesting new records to the butterfly fauna of the region we are researching, including Mountain Alcon Blue, Purple Emperor, White-letter Hairstreak, Blue-spot Hairstreak, and possibly this Reverdin's Blue. The school summer holidays are soon to begin and he is impatiently waiting to resume his searches in the the mountains around our village and see what else he can add to his list. We have already topped 70 species just in the surrounding meadows and glades!