Adscita geryon (Hübner, 1813)

Host plants:
Helianthemum nummularium and other species of Helianthemum. In the high Alps Helianthemum alpestre is often the source of high-abundance populations (e.g. Ofenpass region in Switzerland or Großglockner in Austria). In rearing the larvae also accept Geranium. Occasionally larvae may switch to Geranium also in the field (when both plants are mixed). If there is oviposition on Geranium in the field, too, has still to be investigated in the field.

Habitat:
Adscita geryon colonizes limestone grasslands and Alpine meadows and pastures up to more than 2400m above sea level.

Life cycle:
After hibernation the caterpillars are fully-grown often already between late April and mid-May. The moths fly from late June to mid-August, sometimes regionally a bit earlier. Especially in the high mountains most larvae should hibernate at least twice.

Endangerment factors:
Due to habitat loss and improper maintenance (overgrazing, pens, but also abandonment and following succession) Adscita geryon is endangered outside the Alps in central Europe.

Remarks:
Adscita geryon is widespread in Europe, but is missing in the very north and south. It reaches, e.g. central Spain and northernmost Greece (only in the mountains). Outside Europe, it is known only from northern Turkey.

Interestingly the larvae from extra-Alpine Germany and northern Greece are practically identical, wheras those of the ssp. chrysocephala (Alps) are much more variable with common yellow and even sometimes orange forms. The imagines of this subspecies are still smaller than those from central European lowlands.