Graellsia isabellae, the Spanish moon moth, is in the silkmoth family Saturniidae. It is the only species in the monotypic genus Graellsia. The species was first described by Mariano de la Paz Graells y de la Agüera in 1849 and the genus was erected by Augustus Radcliffe Grote in 1896.

Quick Facts Graellsia isabellae, Conservation status ...

Graellsia isabellae
Female
Conservation status
Data Deficient  (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Saturniidae
Tribe:	Saturniini
Genus:	Graellsia Grote, 1896
Species:	G. isabellae
Binomial name
Graellsia isabellae (Graells, 1849)
Distribution of G. isabellae in western Europe
Synonyms
Graellsia isabellae paradisea Marten, 1955 Graellsia isabellae roncalensis Gómez Bustillo & Fernández Rubio, 1974 Attacus isabellae Saturnia isabellae Graëlls, 1849 Actias isabellae (Graëlls, 1849)

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This moth is native to Peninsular Spain. They live high up in the Pyrenees and other mountain ranges where the climate is cold. There is a small representation in some places located in France and Switzerland where they are not native but instead further generations of captive moths through repopulation attributed to human action with specimens from Spain.

They are relics originating from the Ice age or beyond as It is thought that their habitat is a refuge location. This means that for the past few millions of years, while the climate of Europe has drastically changed, the conditions in the small areas in Pyrenees have remained stable, and never changed, allowing the small remnant populations of this moth to survive for thousands of years in these small habitats. They are split off from the lineage of 'Moon Moths', genus Actias.

At the end of April and beginning of May the moth begins to hatch after overwintering in the cocoon. Normally moths from the same parental line won't copulate, so it is necessary to take this into account when the moth is bred in captivity. After copulation the female lays about 100 to 150 eggs on the favoured food plant, pines. The larva hatch after 1 to 1+1⁄2 weeks and begin to eat the very hard pine needles. It takes about one and a half months for the caterpillars to reach the last instar. In the last instar the caterpillars go down from the tree to pupate under leaves on the ground. In this stage the pupae in the cocoon overwinter until the next spring.

The caterpillar primarily eats the needles of pine trees, more specifically Pinus nigra and Pinus sylvestris (genus Pinus). It appears to have difficulty adopting to non-native pine species as a host even within the genus Pinus .

Graellsia isabellae × Actias selene is a hybrid of the Spanish moon moth and the Indian moon moth (Actias selene).^[1][2]