Papilio hospiton Guenée, 1839

Host plants:
The caterpillar lives primarily on Ferula communis (Umbelliferae). Rarely evidently Ruta corsica (Rutaceae) and related species are also used.

Habitat:
Papilio hospiton inhabits mostly sunny, semi-open to open slopes: roadsides, rocky, often bushy slopes, small quarries, mostly woody plants rich pastures, clear places in very loose scrub and oak forest and embankments.

The caterpillars are found mostly on medium-sized, partly also larger, but not flowering perennials of Ferula communis, which often grow under very warm conditions on rock, gravel or open ground. Christian Siegel (Hohenems) told me of numerous caterpillar observations on very small, stunted plants with few leaves (Sardinia), while my own observations succeeded on at least medium-sized herbs. It thus seems to be present a certain plasticity in oviposition behaviour, but a clear preference for microclimatically beneficiary spots is unmistakable.

Life cycle:
The pupa hibernates. The moths usually fly in a single generation from mid or late March to late June (rarely up to early August). The literature reports a very partial second generation. In the second half of May 2012 (e.g. 17. May, 21. May) I observed numerous eggs and caterpillars of all ages and often very worn butterflies in Sardinia in altitudes from 800 to 1100m above sea level (Gennargentu). After a good portion of the larvae was already fully-grown and I also observed feeding traces of already pupated larvae, there must have flown many adults already in early and mid-April or even earlier.

The butterflies are usually observed only briefly as they strive in a restless, fast flight over the terrain. Occasionally they can be watched when visiting flowers or something more common when hilltopping on terrain markings for mating arrangement), where several males often arrive. Papilio hospiton is a good flyer and roams as Papilio machaon far.

The eggs are laid singly on the leaves of the host plant (similar oviposition behaviour as P. machaon). Pupation takes probably place on stones, rocks, wood and stems.

Endangerment factors:
Papilio hospiton is so far not under serious threat thanks to the often well-preserved nature in Sardinia. Local risk factors can both be overgrazing and also too strong tree and bush encroachment in the habitats. The habitats must be preserved also in the future!

Remarks:
Papilio hospiton is endemic to Corsica and Sardinia, and occurs there especially in middle mountain ranges from 400 to 1500m asl (rarely lower or higher). From the fact that not too seldom hybridization with Papilio machaon occurs you can suggest a very close relationship between the two taxa, as well as from the habitual similarity.

Hints on determination:
Papilio hospiton can be determinated by its shorter tails, broader black coloration and smaller orange spots. The similar Papilio machaon is rarer there and occurs more near the coasts.