Boloria dia (Linnaeus, 1767)


Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Adult on Fragaria. The species is satisfied even with unimpressive flowers (eastern Swabian Alb, mid-May 2013) [N] Boloria dia: Male (eastern Swabian Alb near Söhnstetten, Germany, mid-May 2013) [N] Boloria dia: Adult (eastern Swabian Alb, mid-May 2013) [N] Boloria dia: Adult (eastern Swabian Alb, Germany, June 2013) [N] Boloria dia: Female (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Female (eastern Swabian Alb, Southern Germany) [N] Boloria dia: Female [N] Boloria dia: Adult (N-Greece, Smolikas near Samarina, late June 2013) [N] Boloria dia: Upper side [N] Boloria dia: Lower side [N] Boloria dia: Mating [N] Boloria dia: Oviposition (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Oviposition (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Oviposition (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Oviposition (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Oviposition (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Oviposition (eastern Swabian Alb, S-Germany, mid-May 2013) [N] Boloria dia: Ovum at the fruit of Vicia sepium (eastern Swabian Alb) [N] Boloria dia: Egg (eastern Swabian Alb, mid-May 2013) [M] Boloria dia: Half-grown larva (eastern Swabian Alb, Southern Germany) [N] Boloria dia: Larva after the last moult  [S] Boloria dia: Larva (eastern Swabian Alb, Southern Germany) [S] Boloria dia: Larva (eastern Swabian Alb, Southern Germany) [N] Boloria dia: Larva [N] Boloria dia: Larva at Viola hirta [N] Boloria dia: Pupa [S] Boloria dia: Larval habitat (nutrient-poor grassland) [N] Boloria dia: Habitat: nutrient-poor meadow at the woodland margin (eastern Swabian Alb) [N] Boloria dia: Habitat on the eastern Swabian Alb in May 2013 [N]

Host plants:
Viola species, often Viola hirta.

Habitat:
Boloria dia most often colonizes shrub-rich nutrient-poor grasslands, but occasionally forest edges and clearings. In places it is also found in fens. It is largely absent in the Alps.

Life cycle:
Mostly there are three generations between April and September. The caterpillar overwinters mostly in penultimate instar. I found numerous larvae from March to May on Viola hirta, feeding at daytime or resting hidden in the moss around the plants.

Endangerment: endangered

Endangerment factors:
Boloria dia has become quite rare in Central Europe. In areas with more nutrient-poor grasslands as in the Swabian Alb region (Germany) it is still more common. Here Boloria dia even seems to have a rather positive population development at the moment.

Remarks:
The smallest native fritillary in Central Europe can sometimes be surprisingly common in suitable habitats, especially in the second generation.
The distribution extends from Northern Spain across Central and parts of Southern Europe (absent in the far north and far south, in Greece southwards about to Mount Olympus) to Mongolia.



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