Mountain Small White (Pieris ergane)
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2023 photographs highlighted in green. Click on any photograph to go to an enlarged picture, or simply scroll down the page.
A very scarce and localised species in France. Its localities are limited to
the Clarée valley in eastern France and the foothills of the eastern Pyrénées,
although it may have already disappeared from the Clarée valley in the
Hautes-Alpes; I have seen no recent records from that region and the last time I
visited the area, there was exceptionally heavy sheep grazing.
It has two or three broods each year and is probably on the wing from April to August in the locality that I saw it. According to the books, it has three broods in the eastern Pyrénées and flies between 500 and 1000m altitude, but in the Clarée valley it has only two broods and flies between 1200 and 2200m altitude.
It is slightly smaller than the Small White (P. rapae) and has a rather weaker flight. The key distinguishing feature from other Pieris species is that ergane does not have a unf post-discal black spot. In addition, from an upperside view alone, the apical black mark is broadly square.
The female has much heavier upf markings than the male and the second brood
is rather more heavily marked than the first brood in both sexes, as is the case
for all Pieris species.
I was very fortunate in being told where ergane flies. However, it was a hot day and the few male ergane that were flying there were flying slowly up and down the steep slopes of a ravine, not stopping. I had heard that the late afternoon would be stormy and it turned out that a cold wind that preceded the storm persuaded these few males to come down to nectar, mostly on Scabious. So, for short while they nectared before the storm arrived, and, despite being blown about on the Scabious, it was possible to get some sort of photographs.
A visit to the same site in 2023 was a similar experience, with only a quick snap of 51117 being possible, but at least the forewing is sufficiently raised to show the absence of a black spot.
|46248||M||a male of the summer brood.||570|
|46226||M||an underside view, showing the absence of the unf post-discal spot. 46237 and 46246 are the same individual.||570|
|46237||M||a view from the other side.||570|
|46246||M||a view with the wings very slightly open, enabling a view of the square apical mark.||570|
|51117||M||a male, the unh being quite pale in comparison to the one seen in 2019.||570|