Host plants:
The caterpillar lives on Euphorbia species such as Euphorbia nicaeensis, E. characias, E. peplis. In southern Europe Euphorbia nicaeensis can be regarded as main host plant. Here I found my larvae in the southern Cevennes.
Habitat:
Hyles nicaea inhabits warm dry slopes, xerothermic, nutrient-poor and grazed grasslands (sheep, goats, cattle, horses), rocky areas, sparse scrub with dry grasslands, steep slopes in river areas and similar locations. Often the sites are quite heavily grazed areas where Euphorbia nicaeensis and other euphorbias are abundant.
Life cycle:
The pupa hibernates. The moths usually fly in one generation from late May to July/early August with peak in June and early July. Very rarely there is a very partial second generation in August/September, as an emergence without hibernation shows (2012, in breeding). This is supported by occasional but reliable observations of larvae in September, e.g. in Southern France (internet-based data).
The young caterpillars live mostly on the lower leaf surface. The larger caterpillars rest on the stems and are often found feeding in the bright sunshine. I found caterpillars between the second and the fifth (final) instar) in the southern Cévennes (France) in hot pastures on 21/07/2012 . Overall, the caterpillars are observed from mid or late June to September (rarely later) with clear maximum from mid-July to early August. Pupation takes place in a very dense cocoon in the soil (below the mull layer and rather flat in the ground).
Endangerment: endangered
Endangerment factors:
Hyles nicaea requires large suitable landscapes and is threatened by intensification (agriculture, overbuilding), as well as by abandonment of grazing and subsequent bush encroachment and reforestation. The latter is presumably the main reason for decline for example in Southern France.
Remarks:
Hyles nicaea occurs in the mountains of Northwest Africa up to about 2200m above sea level. In Southern Europe it is found more in the low to (most often) medium-high altitudes up to 1500m above sea level. The occurrence is only very scarce and sporadic from southern Portugal across Spain, Southern France, Italy, Croatia, Albania to Greece, so that indigenity is only proven for some areas. The best European populations occur in the south of France from the Alpes-Maritimes in the east across the Provence and the southern Massif Central to the neighbourhood of Carcassonne in the west.
Hyles nicaea is distributed in the east from Asia Minor and the southern Crimea to Central Asia.