Satyrium w-album (Knoch, 1782) White-letter Hairstreak, Ulmen-Zipfelfalter, Thecle de l'orme/ W blanc, Хвостатка вязовая
Distribution and biological peculiarities in Armenia: The species is found troughout much of Europe, including Scandinavia, as far as the Urals, and occurs again in the far East, including Japan. The butterfly has a widely disjunct distribution across the northern hemisphere but is absent in North America. Armenia is inhabited by nominate subspecies. In Armenia the species inhabits wide variety of woodlands and forests between 1000 and 2200 m a.s.l. The host plant of the species in Transcaucasia is Ulmus glabra. Flight period is between early June and mid August (depending in elevation) in a single generation.
Population dynamics: The species is fairly uncommon within a typical habitat, which partly might be result of its crypticbehavior as the butterflies spend quite a lot of time in canopy. The population trend of the species during 2003-2013 demonstrates stability (p>0.05), which is probably justified by resistance of it host plant towards various threats except deforestation in clear-cut manner, as even the selective cutting can open a necessary space for the butterflies to feed on flowers. Moreover it is supposed that after massive deforestation during 1990-s, the host plant Ulmus glabra started occupation of new space as it one of the first occupies clearings. Unfortunately scarce records in the period before 2003 doesn't allow making justified conclusions.
Conservation measures: The species has not been evaluated for IUCN Red List and for Red Book of Animals of Armenia (2010), however it was included in the European Red List of Butterflies (2010) as Least Concern. Also the species is not included in CITES and in the Bern Convention. Preliminary assessment of its conservation status also suggests it as a Least Concern. Some populations of the species are protected in Dilijan National Park, Zangezur Biosphere Complex, and Khosrov Forest State reserve.Also populations of the species are covered by some Emerald Sites. Thus, there is no necessity for specific conservation measures; however it is important to continue the monitoring of the species to track the changes in woodland ecosystem.