Actias isabellae (Graëlls, 1849)

Host plants:
The caterpillar lives on pine (Pinus species), mainly Pinus sylvestris, P. laricio and some others.

Habitat:
Actias isabellae inhabits pine forests in medium high mountain areas from 900 to 1800m above sea level. It prefers sunny, but not too dry stocks, often a few hundred meters above streams and lakes on steep slopes.

Life cycle:
The pupa hibernates. The moths fly mainly from mid-April to late May (total: late March to early July).

The caterpillars live from May to mid-August. I found it almost fully-grown on 7 July 2012 in the Hautes-Alpes (France) at about 1100m above sea level on the lower branches of medium old pine accompanied by a mature caterpillar of Dendrolimus pini and young caterpillars of Hyloicus pinastri.

Pupation takes place on the ground in a less solid and less clearly shaped cocoon than in Saturnia.

Endangerment factors:
Actias isabellae is locally threatened by habitat loss (e.g. cultivation of other wood species, deforestation, forest fires), however, hardly by collectors, who can not endanger healthy populations in sufficiently large habitats (at most in weak, local populations which have already declined due to the other factors).

Remarks:
Actias isabellae is endemic to southwest Europe and occurs only in Spain (locally from the mountains of Andalusia such as Sierra de Cazorla to the Pyrenees) and France (eastern Pyrenees and southern Alps, locally also in the Jura: introduced?) autochthonously. In France, it is particularly common in the Hautes-Alpes in the Durance valley and its adjoining valleys, but is also resident in adjacent areas (Alpes-de-Haute-Provence, Drome etc.). In Switzerland a introduced but established population is known in the Upper Valais. From northwestern Italy, there are so far only unconfirmed informations. Here an occurrence would not be unlikely for example in the upper Susa valley.