Maculinea nausithous Bergstrasser, 1779 Dusky Large Blue, Dunkle Wiesenknopf-Ameisenbläuling, Azuré des paluds, Голубянка навзитой, Մթնշաղային կապտաթիթեռ.
and biological peculiarities in Armenia: The species is distributed at northwest Spain and from central eastern France, Switzerland, Germany and eastwards up to Russia, Kazakhstan, and Caucasus. Monotypic. Female lays eggs in the flowers of Sanguisorba officinalis. The species is in parasitic relations with ants Myrmica rubra, that is why the second and third instar larvae are moving to ant hill where they feed on larvae and pupae of the ants. In the anthill they spend the winter, and after they finish feeding and start pupation. In Armenia the species inhabits wet meadows and marsh-like habitats, sometimes located at clearings in the forests, but more often at the upper timberline and above occupying range from 1700 to 2200 m a.s.l. Flight period is mainly from late July to mid August in single generation.
Population dynamics: The species has a patchy distribution, which requires special efforts on its regular monitoring. Therefore the existing data is insufficient for calculation of its population trends and require longer period of regular surveys. Nevertheless, particular efforts for survey of its population have been undertaken in 2011. The results of the survey demonstrated that abundance of the species at the typical undisturbed habitat is medium to high. However, some populations of the species disappeared in the areas of intensive mowing (using cutting machines), and in the areas where streams have been put into pipes as water supply. Both factors appear to be major sources of population decline, as in the first case the grass is cut in the season of blooming of the host plant Sanguisorba officinalis, and in the second the wet areas where the host plant could grow, have disappeared. Need to mention that the host ants have not been yet defined for the Armenian populations of the species, and therefore their role in population decline is still unclear.
Conservation measures: The species is included in IUCN Red List as Lower Risk/Near Threatened, in European Red Book as Vulnerable, in the Red Book of Animals of Armenia as Vulnerable VU B1a+B2a, and in the Appendix II of Bern Convention. Some populations of the species are protected in Dilijan National Park, however majority is located outside of existing protected areas. Therefore assessment of its distribution sites under Bern Convention and their inclusion into network of Emerald Sites is the first step. It will allow to develop alternative approaches to mowing and use of water resources, and then to begin working with farmers and local municipalities. At current the species is considered in the process of assessment of Prime Butterfly Areas (PBA) in Armenia (see the page Prime Butterfly Areas).