Graellsia isabellae

Graellsia isabellae - Spanish Moon Moth Distribution Endemic to mountainous regions of France and Spain. Has been observed in Switzerland as an introduced population; that Swiss population may derive from individuals from Spain and France. The species is often called the “Stained Glass” moon moth. It is a relict species, surviving in stable refugial mountain habitats over long geological times. Biology & Life Cycle Voltinism: Univoltine (one generation per year). Flying period: Adults are found from April to July, depending on local climate. Wingspan: About 60–100 mm (medium-sized) Host plants: Larvae feed only on pines (Pinus spp.), especially Pinus nigra and Pinus sylvestris. In captivity, other Pinus species may be accepted, though the moth in the wild is quite specialized. Rearing & Husbandry Notes Eggs & Early Instars Eggs hatch in 10 to 15 days (depending on temperature) After hatching, larvae should be placed on cuttings of pine (fresh, pesticide-free) in well-ventilated containers. Young larvae (L1–L2) can be reared in plastic boxes with ventilated lids. Later Instars & Growth From L3 onward, larvae may be transferred to sleeves (mesh “bags”) or larger ventilated cages. It is possible to rear the caterpillars from egg to cocoon in ventilated boxes, provided they are kept extremely dry. Moisture control is critical: Many breeders fail with G. isabellae because they keep larvae too wet. Replace pine twigs every 3–5 days. Keep the container clean of frass (droppings) and mold. Avoid overcrowding: stress from contact causes smaller, weaker adults and higher mortality. Pupation & Overwintering After 5 instars, larvae spin cocoons. They can be offered moss or similar substrate in which to spin. Cocoons must be kept dry. They are tolerant of cold and frost, indeed, the species’ wild habitat experiences freezing winters. Overwinter the cocoons in a cold, dry place (e.g. cellar, garden shed, or outdoors in garden in many temperate climates). Be cautious with fridges, humidity inside fridges may dry cocoons too much and lead to death. Adult & Breeding Some adult males show little or no mating drive (“apathic” males) in captivity this is a known challenge. Hand-pairing is possible but more suited for experienced breeders. One technique: keep virgin females alone, then introduce males at night when females are calling. The species hybridizes readily with Actias genus moths in captivity, showing its close affinity.