Mountain Argus (Aricia artaxerxes)
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2022 photographs highlighted in blue. Click on any photograph to go to an enlarged picture, or simply scroll down the page.
|22903_male_Valais, Switzerland_22Jul10||12963_male_Valais, Switzerland_15Jul08||18191_male_Isère_12Jul09||17800_male_Hautes-Alpes_10Jul09|
Artaxerxes is very similar to the Brown Argus (A. agestis) although it occurs at higher altitudes where it can still co-exist with agestis. Artaxerxes is quite common at altitude, and often encountered in good numbers. The differences between artaxerxes and agestis are discussed on the agestis page. That artaxerxes also has a slightly more pointed forewing apex than agestis is clearly apparent in most of the above photographs, perhaps best in 18191, although 21512 has a sufficiently rounded forewing margin to suggest the possibility of agestis.
As with agestis, the upperside lunules of the female artaxerxes are nearly always better developed and more extensive.
The nominate form of artaxerxes occurs in the UK
where is known as the Northern Brown Argus. It occurs principally in Scotland
where the upf discoidal spot is white, making the species very easy to identify. In
the few sites in northern England, where artaxerxes is in decline, the
discoidal spot is usually dark brown or black, although some (5-10% according to
may be white or sometimes white-ringed.
In France, the subspecies allous occurs in the Pyrénées and high Alpes; it is generally small and the ups lunules are usually confined to the hindwing. The subspecies montensis occurs in the Basses Alpes as well as the mountain ranges of the Jura, Vosges and the Massif Central; it is generally larger and the underside ground colour light creamy-grey to creamy-brown with well developed orange lunules (there are some on this page that are clearly allous but have extensive orange lunules, though, e.g. 12996). I suspect all on this page are allous except maybe 22527.
In 2019, montensis was classified as a separate species. Presumably allous is now considered to be the nominate form artaxerxes in so far as allous is not mentioned in the new taxonomy listing.
very typical of artaxerxes.
weak uph lunules and only vestigial upf lunules in s2-4.
weak uph lunules and only vestigial upf lunules in s2-4. Does the lower altitude indicate that 18191 is montensis, even though it has the appearance of allous?
rather more than vestigial lunules, extending from s1-s4.
|39164||M||from the Hautes-Pyrénées, perhaps with more extensive orange lunules.||1600|
|41341||M||a male taking salts from the ground, as this species is an avid "puddler". This individual has very reduced orange marginal lunules, completely absent on the forewing and very vestigial on the hindwing.||1960|
a rather grey unf ground colour.
slightly dark shading to the unf lunules and generally darker and greyer unf ground colour.
rather rounded wings and extensive orange lunules, not typical artaxerxes (most here are clearly elongated in appearance) and I have my doubts as to whether this may be agestis, as indicated above.
puddling with many other blues, with a rather scruffy Small Blue (Cupido minimus) in the background.
a typical male.
a typical male, possibly montensis on the basis of the creamy brown ground colour and lower altitude.