Fluturat e Shqipërisë
Butterflies of Albania

Sylvain Cuvelier =
Anila Paparisto =

Last update: 05.viii.2023

Phengaris arion / Large Blue
Kaltëroshja njollazezë
Lycaenidae - Polyommatinae

Phengaris arion (Linnaeus, 1758). TL: Nuremburg, Germany.

1a. Phengaris arion, distribution map. Historical data ; Additional data from the 2018 update ; New observations since the 2018 update.
1b. Phengaris arion ♂ undersdie. Romania (© Sylvain Cuvelier)

Description
♂♂
Small to medium-size butterfly. Fw: 16-20 mm.
Ups: bright blue gc, white fringes, broad black marginal borders.
Upf: variable series of elongated, black postdiscal spots (rarely absent)
Uph: variable, small postdiscal spots (sometimes absent)
Uns: grey to grey-brown gc, fringes chequered, usual markings strongly marked.
Unh: extensive green-blue basal suffusion.
♀♀
Slightly larger.
Ups: bright blue gc, white fringes, broad black marginal borders.
Upf: often larger elongated, black postdiscal spots.
Uns: similar as ♂♂.

Similar species

Phengaris alcon Size: similar or slightly smaller. Upf: ♂♂ no pd black spots. Upf: ♀♀ pd black spots touching black border. Upf: ♂♂ 1-2 mm black marginal border. Uph: no pd spots. Unf: no cell-spot. Unf: small pd spots. Unf: one row of grey-black marginal spots. Unh: gc grey-brown with pale basal flush. Unh: one row of black marginal spots.

Life cycle
Adults: single generation from June to early August.
Egg: 6-8 days.
Caterpillar: short feeding period on the fooplant (about 17 days), overwintering in ants nest as L4 larva, feeding again in spring in the ants nest.
Pupa: about 24 days.

Habitat
Phengaris arion inhabits rough grassy places with thyme in shrubby places with abundant flowers from 250 to 2000 m a.s.l.
Spatial requirement modest, population density moderate.

Foodplants
Caterpillars feed on different Thymus sp., also mentioned is Origanum vulgare.
Butterflies feed on the foodplants of the caterpillar.

Distribution
Albania: widespread in the Northern Albanian Alps, local in other mountain areas.
Balkan: AL - BG - BIH - GR - HR - NMK - MNE - RKS - RO - SLO - SRB
Europe: IB - IT - ALP - BAL - NWE - UK (reintroduced) - SCA* - EEU
Local in Asia Minor, Transcaucasia, Caucasus and further east.

Conservation status
Phengaris arion is not endangered.
Albanian Red List: CR.
IUCN Red List, category at the Mediterranean level: LC.

Useful links
Bink 2015
Pyrgus.de
Lepiforum
Euroleps

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