Gavarnie Blue (Plebejus pyrenaicus)

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2016 photographs highlighted in green. Click on any photograph to go to an enlarged picture, or simply scroll down the page.

39034_male_Hautes-Pyrénées_23Jul15

39032_male_Hautes-Pyrénées_23Jul15

I have very strong doubts that this is actually pyrenaicus. I thought it was at the time, because I was in a location where this species was relatively common albeit toward the end of its flight period. It is a highly localised and rather uncommon species of the Pyrénées and the Cantabrian mountains in Spain. However, the Glandon Blue (P. glandon) also flies in the Pyrénées and the two species are very similar. I had a brief view of the underside and an even briefer view of the upperside before it departed, never to be seen again. From the underside view, it looked very different to glandon, which I see frequently in the Alpes, although, given the geographical separation of these populations, this is perhaps not surprising.

They key differentiating feature is said by Lafranchis to be the unf submarginal marks which are grey for glandon and black for pyrenaicus. The marks on 39032 appear to be much closer to black than to grey and, on comparison to my photographs of glandon, considerably darker. My photographs of glandon show these marks to vary from ghosted to mid-grey. However, whether 39032 is actually black, is another matter, and it probably is not. It was not until much later that I looked closely at the brief upperside view afforded by 39034 that I concluded that it looked a 100% match for what would be expected for glandon, whereas the books and other reference sources show the pyrenaicus upperside to be a much paler grey-blue with significantly narrower borders. I feel this is conclusive evidence for glandon but I will leave the page here in order to elicit expert opinion on my reasoning, and well as to have a page ready for when I actually do see pyrenaicus in the future.

ref

sex

observations

alt. m

39034

M

I suspect the upperside is just not pale enough for pyrenaicus.

1600

39032

M

the underside of 39034.

1600

 

39034_male_Hautes-Pyrénées_23Jul15

 

39032_male_Hautes-Pyrénées_23Jul15