Abstract.

Papilio alexanor Esper, 1800 is a strictly protected butterfly in Europe, where its previously known range is restricted to south-eastern France, north-western Italy, and parts of the Balkan Peninsula. In Italy, stable reproducing populations had been detected exclusively within Liguria and Piedmont. Regarding southern Italy, only scattered historical records had been documented, leading researchers to speculate that no established populations had existed in this region. Below is the first documented evidence of stable reproducing populations of P. alexanor in southern Italy, discovered along the border between Campania and Basilicata. Field surveys were conducted during April-May 2025 and April-May 2026. A reproducing population was confirmed, concentrated at two main sites covering an area of approximately 1 km². Ferula glauca L. is documented here for the first time as a larval host plant of P. alexanor in Italy; prior to this record, the host plants documented belonged to other ecologically and morphologically distinct Apiaceae genera. Use of Ferula species had previously been reported for Balkan and Asian populations. The early flight phenology (early April to the end of May) is markedly earlier than in northern Italian and French populations. We suggest that this phenological mismatch, combined with the difficult access to the cliff habitats, may partly explain the absence of previous records, though the origin of these remains to be determined. The biogeographic and conservation implications of these findings are being discussed, including the need to revise the species’ conservation status under the European Habitats Directive and the IUCN Red Lists.

Introduction

The Southern Swallowtail Papilio alexanor Esper, 1800 is a butterfly inhabiting the southern portion of the western Palaearctic region. Its range extends from western Europe (southern France) eastward to Kyrgyzstan and northern Afghanistan (Bollino and Sala 2004; Balletto et al. 2023). The distribution is highly fragmented, comprising widely disjunct populations of varying size.

In Europe, the range includes a wide area of south-eastern France, from the coast up to the Alps, the westernmost part of Liguria, and some valleys in south-western and north-western Piedmont, Italy (Lafranchis et al. 2015; Anselmo 2021; Balletto et al. 2023; Anselmo et al. 2025) and the Valais in Switzerland as an anthropogenically introduced population (Gerber 2015). Historical records from Calabria and Sicily, spanning from 1918 to 1985, have never been followed by confirmation of a stable population (Table 1). The species is broadly distributed in the southern Balkan Peninsula, particularly in Greece, where it is well established both on the mainland and on several Ionian and Aegean islands (Bollino and Sala 2004). A small population is known from the Croatian coast (Verovnik and Švara 2016), and a single individual was recently recorded from Serbia (Vukajlović et al. 2025). Beyond Europe, the species occurs in Anatolia, the Caucasus region, Syria, Lebanon, Israel, Iran, Turkmenistan, Uzbekistan, Kazakhstan, and Kyrgyzstan (Bollino and Sala 2004; Kudrna et al. 2011). European populations are only slightly differentiated, showing a few characteristic mutations between the Franco-Italian and Balkan lineages. Greater differentiation is observed when comparing them with Middle Eastern populations (Dapporto et al. 2022; Nazari et al. 2025).

Table 1.

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Historical observation of P. alexanor Esper, 1800 in Southern Italy.

Historical observations of Papilio alexanor Esper, 1800 in Southern Italy
year	region	locality	object	author	bibliography
1918	Calabria	San Luca	Worn male	Turati	Turati (1919)
1920	Calabria	San Luca	Worn male	Stauder	Stauder (1923)
1927	Sicily	Nizza di Sicilia	Worn male	Stauder	Stauder (1928)
1973	Sicily	Taormina	observation	Henriksen	Henriksen (1981)
1980	Sicily	Linguaglossa	Worn male	Henriksen	Henriksen (1981)
1985	Calabria	near Morano (CS)	female, laying eggs	Gulli	Bollino and Sala (2004)

The last documented evidence of a female ovipositing in southern Italy dates to 1985, near Morano Calabro, and was not confirmed by subsequent surveys at the same locality (Bollino and Sala 2004). More recently, two unpublished observations retrieved from the citizen science platforms iNaturalist.org and Observations.org have come to the authors’ attention: the first one of an individual apparently engaged in oviposition behaviour on a yellow-flowered umbellifer in Basilicata (2023, observer: Luigi Campagna), the second one a female individual resting on a Valeriana rubra L. in Campania (2024, observer: LennartH) and a third-instar larva in Sicily (2024, observer: gius8890). None of these records were accompanied by confirmed host plant identification, and the Sicilian locality could not be confirmed during a field visit by the authors in June 2025.

P. alexanor is a strongly heliophilous species, occurring from sea level to approximately 1800 m, with a marked preference for open habitats with sparse woody vegetation. It favours steep terrain characterised by cliffs or rocky outcrops, where adults exploit thermal updrafts in flight. At least in Europe, the species appears confined to calcareous substrates (Baruzzi et al. 2016; Balletto et al. 2023; Anselmo et al. 2025).

Throughout its range, P. alexanor is univoltine and oligophagous, with larvae feeding exclusively on Apiaceae. Univoltinism is a direct consequence of the larval diet: caterpillars feed solely on the flowers and developing seeds of the host plant; however, should these edible parts of the floral scape be completely consumed, larvae will also feed on leaves, closely linking adult emergence to its phenology in each area. The flight period may therefore vary considerably among populations, depending on the local host plant used (Balletto et al. 2023; Anselmo et al. 2025). The host plants of north-western Italian populations are Ptychotis saxifraga (L.) Loret & Barrandon and Opopanax chironius (L.) W.D.J.Koch, as confirmed by recent and extensive field observations (Anselmo et al. 2025). Some authors have also reported Trinia glauca (L.) Dumort and Seseli montanum L. as additional host plants (Bollino and Sala 2004; Balletto et al. 2023), but these records most likely reflect misidentification, given the strong morphological similarity between these taxa and the confirmed hosts (Descimon 1991; David and Sanetra 1994; Anselmo et al. 2025). Balkan and Central Asian populations also use several Ferula Tourn. ex L. species (Bollino and Sala 2004; Balletto et al. 2023).

P. alexanor is strictly protected in Europe under Annex IV of the Habitats Directive (Council Directive 92/43/EEC) and Appendix II of the Bern Convention. According to the most recent Article 17 reporting cycle (2019–2024), the conservation status of P. alexanor in Italy is U1 (inadequate) in the Alpine biogeographical region, while it is still not considered present in the Mediterranean Region, although, during the fifth reporting cycle, the presence of two Ligurian populations prompted a request for evaluation in the next reporting round. According to the European Red List of Butterflies, the species is assessed as Near Threatened (NT; Van Swaay et al. 2025), while in Italy it is listed as Endangered (EN; Balletto et al. 2016; Bonelli et al. 2018).

Material and methods

the study area spans the border between the Provinces of Salerno (Campania Region) and Potenza (Basilicata Region), both in southern Italy. The area was selected on the basis of a single iNaturalist record from Basilicata and subsequent prospecting of sites presenting habitat characteristics consistent with the known ecology of P. alexanor. Precise locality data are withheld in this publication to protect the populations from disturbance and illegal collection; locality information is available to conservation authorities and qualified researchers upon request. Field surveys were coordinated by the authors in collaboration with the University of Turin (Department of Life Sciences and Systems Biology) and the Italian Lepidopterological Association (Associazione Lepidotterologica Italiana, ALI), in April and May 2025 and in April and May 2026. Host plant identification was carried out following Pignatti et al. (2017). Plant nomenclature follows the World Flora Online (2026) database (https://wfoplantlist.org). All observations are supported by photographic documentation.

Results

First site

Campania/Basilicata border, Provinces of Salerno and Potenza; Habitats Directive grid cell E480N190; elevation: 50–200 m. Occupied habitat estimated at not less than 0.6 km² (Figs 1, 9).

Figure 1.

New distributional data of P. alexanor in Italy. Orange cells: new reproducing populations recorded in this study (2025–2026). Blue cells: occupied grid cells (10×10 km) as reported in the most recent Italian national reporting under Article 17 of the Habitats Directive (2019–2024). White cells: historical records from southern Italy (see Table 1 for details). (Courtesy of L. Anselmo).

22.iv.2025 Campania/Basilicata border: approximately 10 adults of both sexes, in flight and feeding on V. rubra;

29.iv.2025 Campania/Basilicata border. 5 adults (2 females, 3 males) in flight and feeding on V. rubra (Fig. 2, Campania side);

Figure 2.

P. alexanor, adult (male) feeding on V. rubra 29.iv.2025. Campania/Basilicata border, Campania side. Photo by S. Meraglia.

20.v.2025 Campania side: approximately 100 larvae at various developmental stages on F. glauca (Fig. 3); Basilicata side: approximately 30 larvae at various developmental stages on F. glauca (Fig. 4);

Figure 3.

P. alexanor, larvae of different stages on F. glauca. 20.v.2025 Campania/Basilicata border, Campania side. Photo by S. Meraglia.

Figure 4.

P. alexanor, larva stage L3 on F. glauca maturing seeds. 20.v.2025 Campania/Basilicata border, Basilicata side. Photo by P. Mazzei.

21.iv.2026 Campania side: between 20 and 30 fresh adults of both sexes observed in flight; males and females exhibited high levels of activity, with numerous individuals observed foraging on V. rubra flowers (Fig. 5);

Figure 5.

P. alexanor, a very freshly emerged adult (female) feeding on V. rubra. 21.iv.2026 Campania/Basilicata border, Campania side. Photo by L. Valeri.

23.iv.2026 Campania side: approximately 30 adults of both sexes observed; patrolling and feeding males; females feeding on V. rubra and ovipositing on F. glauca (Fig. 6); one pair in aerial courtship (Fig. 7);

Figure 6.

P. alexanor, female laying egg on F. glauca. 22.iv.2026 Campania/Basilicata border, Campania side. Photo by A. Baruzzi.

Figure 7.

P. alexanor (female on the left, male on the right), courtship flight. 22.iv.2026 Campania/Basilicata border, Campania side. Photo by L. Valeri.

20.v.2026 Campania side: at least 20 caterpillars, from L2 to L4 (Fig. 8) found on F. glauca. The floral stems and maturing seeds of the plant had already been consumed; the caterpillars were actively feeding on the leaves of F. glauca.

Figure 8.

P. alexanor larvae stage L4 on F. glauca. 20.v.2026 Campania/Basilicata border, Campania side. Larvae targeting the leaves of F. glauca after having entirely consumed the floral stems and maturing seeds of the host plant. Photo by Z. Zerunian.

Second site

Basilicata Region, Province of Potenza; Habitats Directive grid cell E481N189 (Fig. 1, Fig. 10); elevation: 450–500 m. Occupied habitat estimated at not less than 0.4 km².

Figure 9.

Habitat and flight area of P. alexanor. 22.iv.2026 First investigation site (Campania/Basilicata regional border). To ensure the protection of this sensitive site, precise locality details and georeferencing have been withheld. Photo by A. Baruzzi.

Figure 10.

Habitat and flight area of P. alexanor. 23.iv.2026 Second investigation site (Basilicata region). To ensure the protection of this sensitive site, precise locality details and georeferencing have been withheld. Photo by A. Baruzzi.

23.iv.2026: 3 patrolling males; 1 female ovipositing on F. glauca;

20.v.2026: At least five males were observed patrolling the area in flight, while a female was ovipositing on F. glauca near the site, where maturing eggs and an L2 larva moulting into L3 (Fig. 11) were also found on neighbouring plants along the trail.

Figure 11.

Larva L2 (moulting to L3) of P. alexanor. 20.v.2026 Second investigation site (Basilicata region). Photo by E. Baccellini.

Based on field monitoring, photographic documentation, and observations of preimaginal stages, the distribution of P. alexanor in Italy has been updated (Fig. 1). All newly recorded localities fall within the Mediterranean Bio-geographical Region, aligning with the species’ priority status under the Habitats Directive.

Habitat

The geology of the study area (Salerno and Potenza Provinces) belongs to the Tyrrhenian margin of the Southern Apennines, classically defined as a ‘fold-and-thrust belt’ or ‘nappe pile’ (Ippolito et al. 1973; Mostardini and Merlini 1986; Sgrosso 1988; Ciarrapica and Passeri 1998). Along the coast, the outcropping formations belong to the Meso-Cenozoic domains of the Campano-Lucana carbonate platform (Alburno-Cervati-Pollino Unit). These include the Upper Cretaceous Rudist/Radiolitid Limestone and the Paleocene–Eocene Trentinaria formations, both characterised by medium-bedded calcarenitic, calcilutitic, and dolomitic limestones rich in macro- and microfauna. Due to the high permeability of this bedrock, the resulting landscape is typically rugged, rocky, and arid.

Both sites are characterised by Mediterranean vegetation dominated by Ampelodesmos mauritanicus (Poir.) T. Durand & Schinz and Euphorbia dendroides L. (Fig. 9). The maquis includes Quercus ilex L., Quercus pubescens Willd., and Pinus pinea L. in the arboreal layer, and Myrtus communis L., Phillyrea latifolia L., Pistacia lentiscus L., Olea europaea L., Arbutus unedo L., Salvia rosmarinus Spenn., Erica sp., and Cistus sp. in the shrub layer. F. glauca is the sole Ferula species present at both sites (Fig. 10).

According to Pignatti et al. (2017), F. glauca is a robust Mediterranean large perennial herb widely distributed across Southern Italy, with documented populations spanning Calabria, Puglia, Basilicata, and Campania, primarily thriving in arid, uncultivated garrigues and rocky calcareous soils. Phenologically, this perennial plant initiates vegetative growth during the winter rains, developing dense, glaucous-green foliage. The sprawling inflorescence emerges in mid-spring, with the main flowering period concentrated between April and June (Pignatti et al. 2017; Bartolucci et al. 2018). Notably, this phenological timeline exhibits strong latitudinal variation, with southern populations initiating vegetative and floral development earlier in response to milder winter temperatures and high spring thermoperiods (Blondel et al. 2010). This specialised seasonal synchronisation ensures the availability of tender umbels and abundant biomass, matching the oviposition and larval development phases of P. alexanor.

Discussion

The discovery of a reproducing population of P. alexanor in southern Italy, approximately 790 km of linear distance from the nearest previously known Italian population, constitutes a significant finding for the biogeography and conservation of this protected species. Both main presence sites support active reproduction, confirmed through direct observation of ovipositing females, larvae at multiple developmental stages, and — at the first site — the presence of a pupa at the base of a F. glauca plant. This plant species is hereby confirmed as the larval host plant of P. alexanor for this population. While the use of Ferula species is well established for Balkan and Central Asian populations (Balletto et al. 2023), it had not previously been recorded in Italy or France, where the species relies on P. saxifraga and O. chironius (Anselmo et al. 2025). The use of F. glauca specifically has been documented only recently in the Peloponnese, Greece (Sanetra 2026). Within the monitored areas, F. glauca is clearly the most widespread Ferula species; although F. communis is also present, its distribution is more scattered and primarily restricted to highly anthropised zones. Nonetheless, all observed ovipositions and larvae were exclusively found on F. glauca. Its broad distribution across central and southern Italy (Pignatti et al. 2017) might suggest that additional populations of P. alexanor could potentially occur in currently unsurveyed areas.

V. rubra is documented as an important nectar source for adults at both sites. Its abundant presence in the frequented biotopes is likely a key resource for adult maintenance throughout the flight period.

The flight period recorded at both sites (early April to the end of May) is earlier than that of known northern Italian populations, which are more tightly coupled to the later phenology of their respective host plants. This early phenology is broadly consistent with the Peloponnesian Greek populations, recently observed laying on F. glauca (Sanetra 2026). The early and relatively brief flight window, combined with the difficult access to rocky cliff habitats, may explain why these southern Italian populations remained undetected for decades.

The presence of larvae at multiple developmental stages simultaneously on the same flowering stem, together with the discovery of a pupa at the base of the same plant, suggests that multiple females may select the same floral scape for oviposition during the flight period. This behavioural pattern warrants further investigation.

The populations discovered have been confirmed as reproducing for at least two years (2025–2026); the 2023 iNaturalist record of a female apparently engaged in oviposition behaviour suggests that a reproducing population may have been present for at least four years. The extent of occupied habitat (0.6 km² and 0.4 km² at the two sites respectively) suggests that conditions may be sufficient to support viable reproducing populations, though dedicated demographic surveys will be needed to confirm this. Historical records from southern Italy had always been interpreted as vagrant individuals or ephemeral occurrences (Bollino and Sala 2004; Balletto et al. 2023); the present data suggest that this interpretation should be reconsidered, at least for this part of the peninsula. However, the origin of these populations — whether long-established, the result of recent natural range expansion, or anthropogenic introduction — cannot be determined from the available data and warrants further investigation.

Being listed under Annex IV of the Habitats Directive (92/43/EEC), P. alexanor is afforded strict protection throughout its range. One of the two sites falls within a Natura 2000 area; as the species is not currently listed among its protected elements, the associated conservation measures do not yet apply to it — a gap that should be urgently addressed. Both the national Red List assessment and the Habitats Directive conservation status should be revised in light of the data reported here. The high desirability of P. alexanor among collectors makes both adults and larvae particularly vulnerable to poaching.

The present findings call for a number of urgent research and conservation actions. Long-term population monitoring at both sites should be initiated in compliance with Habitats Directive requirements. Systematic surveys of adjacent areas in Campania, Basilicata, and Calabria are needed to assess the true extent of the species’ presence in southern Italy, guided by the distribution of calcareous cliff habitats and F. glauca. Historical localities should be re-surveyed during the phenological window documented here (early April–end of May), which differs substantially from that of northern Italian populations. The possibility of additional larval host plants at higher elevations, where F. glauca may be replaced by other Apiaceae, also warrants investigation. The genetic characterisation of these populations, in relation to other European populations of P. alexanor, would be essential to clarify their origin and phylogeographic affinities. Finally, the assessment of ecological connectivity between the newly discovered sites and known populations, building on analyses already conducted for the Maritime and Ligurian Alps (Anselmo et al. 2025), would contribute to understanding the broader metapopulation structure of this species in Italy.

Acknowledgements

The work was carried out with the permission of the Ministry of the Environment and Energy Security (Protocol no.: 38651 – dated 20/02/2026 – Ministero dell’Ambiente e della Sicurezza Energetica). We are grateful to:

Professor Simona Bonelli – University of Turin – Department of Life Sciences and Systems Biology, for their support, advice, and critical reading of this article;

Dr. Luca Anselmo – University of Turin – Department of Life Sciences and Systems Biology, for his support, advice, sharing of information and knowledge, as well as for his long-standing interest in this species;

Dr. Gianluca Bencivenga, for providing geological information regarding the monitored areas;

Emanuela Baccellini, for providing photos of eggs and larvae.

References

Anselmo L (2021) New distributional data of the protected butterfly Papilio alexanor Esper, 1800 in north-western Italy and some ecological observations (Lepidoptera Papilionidae). Biodiversity Journal 12(1): 21–26. https://doi.org/10.31396/Biodiv.Jour.2021.12.1.21.26

Anselmo L, Caprio E, Baruzzi A, Serafini M, Bonelli S (2025) Where and how to conserve butterflies amid climate change: a model-based approach on Papilio alexanor. Biodiversity and Conservation 34: 4575–4615. https://doi.org/10.1007/s10531-025-03170-2

Balletto E, Bonelli S, Barbero F, Casacci LP, Sbordoni V, Dapporto L, Scalercio S, Zilli A, Battistoni A, Teofili C, Rondinini C (2016) Lista Rossa IUCN delle Farfalle Italiane — Ropaloceri. Comitato Italiano IUCN e Ministero dell’Ambiente e della Tutela del Territorio e del Mare, Roma.

Balletto E, Barbero F, Bonelli S, Casacci LP, Dapporto L (2023) Fauna d’Italia, vol. LIV. Lepidoptera Papilionoidea Butterflies. Calderini, Rimini.

Bartolucci F, Peruzzi L, Galasso G, Albano A, Alessandrini A, Ardenghi NMG, Astuti G, Bacchetta G, Ballelli S, Banfi E, Barberis G, Bernardo L, Bouvet D, Bovio M, Cecchi L, Di Pietro R, Domina G, Fascetti S, Fenu G, Festi F, Foggi B, Gallo L, Gottschlich G, Gubellini L, Iamonico D, Iberite M, Jiménez-Mejías P, Lattanzi E, Marchetti D, Martinetto E, Masin RR, Medagli P, Passalacqua NG, Peccenini S, Pennesi R, Pierini B, Poldini L, Prosser F, Raimondo FM, Roma-Marzio F, Rosati L, Santangelo A, Scoppola A, Scortegagna S, Selvaggi A, Selvi F, Soldano A, Stinca A, Wagensommer RP, Wilhalm T, Conti F (2018) An updated checklist of the vascular flora native to Italy. Plant Biosystems-An International Journal Dealing with all Aspects of Plant Biology 152(2): 179–303. https://doi.org/10.1080/11263504.2017.1419996

Baruzzi A, Bendazzi I, Caimi C, Pezzi G, Sala G (2016) Osservazioni sul Papilio alexanor radighierii Sala & Bollino, 1991 (Insecta Lepidoptera Papilionidae). Quaderno di Studi e Notizie di Storia Naturale della Romagna 44: 127–162.

Blondel J, Aronson J, Bodiou JY, Boeuf G (2010) The Mediterranean Region: Biological Diversity in Space and Time. Oxford University Press, Oxford.

Bollino M, Sala G (2004) Synopsis of Papilio alexanor Esper, 1799. Natura Edizioni Scientifiche, Bologna.

Bonelli S, Casacci LP, Barbero F, Cerrato C, Dapporto L, Sbordoni V, Scalercio S, Zilli A, Battistoni A, Teofili C, Rondinini C, Balletto E (2018) The first red list of Italian butterflies. Insect Conservation and Diversity 11(5): 506–521. https://doi.org/10.1111/icad.12293

Ciarrapica G, Passeri L (1998) Evoluzione paleogeografica degli Appennini. Atti Ticinesi di Scienze della Terra (Serie Speciale), 3: 223–244.

Dapporto L, Menchetti M, Vodă R, Corbella C, Cuvelier S, Djemadi I, Gascoigne-Pees M, Hinojosa JC, Lam NT, Serracanta M, Talavera G, Dincă V, Vila R (2022) The atlas of mitochondrial genetic diversity for Western Palaearctic butterflies. Global Ecology and Biogeography 31: 2184–2190. https://doi.org/10.1111/geb.13579

David C, Sanetra M (1994) Verbreitung, Biologie und Autökologie von Papilio alexanor Esper, 1799 in der südwestlichen Alpenregion (Lepidoptera: Papilionidae). Nachrichten des Entomologischen Vereins Apollo 15(1–2): 1–24.

Descimon H (1991) Le choix des plantes nourricières chez quelques Papilionidae et Pieridae provençaux et méditerranéens (Lepidoptera: Papilionoidea). Ecologia Mediterranea 17: 51–61. https://doi.org/10.3406/ecmed.1991.1689

Gerber H (2015) Papilio alexanor Esper, 1799 im Zentralwallis, Schweiz (Lepidoptera: Papilionidae). Entomo Helvetica 8: 206–208. https://doi.org/10.5169/seals-985954

Henriksen HJ (1981) Segnalazioni faunistiche italiane (N. 1–8). 8. Papilio alexanor Esper. Bollettino della Società Entomologica Italiana 113: 50–51.

Ippolito F, D’Argenio B, Pescatore T, Scandone P (1973) Unità stratigrafico-strutturali e schema tettonico dell’Appennino Meridionale (Istituto di Geologia e Geofisica dell’Università di Napoli, Memoria n. 15). Università di Napoli.

Kudrna O, Harpke A, Lux K, Pennerstorfer J, Schweiger O, Settele J, Wiemers M (2011) Distribution Atlas of Butterflies in Europe. Gesellschaft für Schmetterlingsschutz, Halle, 576 pp.

Lafranchis T, Jutzeler D, Guillosson JY (2015) La Vie des Papillons: Écologie, Biologie et Comportement des Rhopalocères de France. Diatheo, Paris.

Mostardini F, Merlini S (1986) Appennino centro-meridionale: Sezioni geologiche e proposta di modello strutturale. Memorie della Società Geologica Italiana 35: 177–202.

Nazari V, Dupuis JR, Habel JC, Bollino M, Schönberger D, Chapman EG, Todisco V (2025) Peering into the past and predicting the future of the threatened southern swallowtail, Papilio alexanor Esper, 1799 (Lepidoptera: Papilionidae). Biological Journal of the Linnean Society 146: blaf078. https://doi.org/10.1093/biolinnean/blaf078

Pignatti S, Guarino R, La Rosa M (2017) Flora d’Italia, 2^nd edition. Edagricole, Bologna.

Sanetra M (2026) On the larval host plants of Papilio alexanor Esper, 1777 in southern Greece (Lepidoptera: Papilionidae). Entomologische Zeitschrift 136: 7–11.

Sgrosso I (1988) Nuovi elementi per un più articolato modello paleogeografico nell’Appennino centro-meridionale. Memorie della Società Geologica Italiana 41: 225–242.

Stauder H (1923) Lepidoptera aus Unteritalien, I. Societas ent., 38: 27–28.

Stauder H (1928) Neue Lepidopterenformen aus Sizilien. Lepidopterologische Rundschau 2: 104–110.

Turati E (1919) Nuove forme di Lepidotteri. Correzioni e note critiche. IV. Naturalista siciliano 23: 20–370.

Van Swaay C, Warren M, Ellis S, Clay J, Bellotto V, Allen DJ, Trottet A (2025) Measuring the pulse of European biodiversity. European Red List of Butterflies. European Commission, Brussels. https://doi.org/10.2779/935927

Verovnik R, Švara V (2016) Confirmed recent occurrence of the Southern Swallowtail (Papilio alexanor Esper, 1799) in Croatia (Lepidoptera: Papilionidae). SHILAP Revista De lepidopterología 44(176): 547–552. https://doi.org/10.57065/shilap.713

Vukajlović F, Tot I, Đurić M (2025) First record of Papilio alexanor Esper, [1799] (Lepidoptera: Papilionidae) in Serbia. Acta Entomologica Serbica 30(1): 111–118.

World Flora Online (2026) World Flora Online Plant List June 2026. https://doi.org/10.5281/zenodo.7460141

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

All field activities and specimen handling were carried out under the required permits issued by the Ministry of the Environment and Energy Security (Ministero del’Ambiente e della Sicurezza Energetica: Protocol no. 38651, dated 20 February 2026).

Artificial Intelligence (AI) use

The authors accept full responsibility for the content of the manuscript, including the disclosure of any use of AI.

No AI tools were used in the preparation of this manuscript.

Funding

No funding was reported.

Author contributions

All authors have contributed equally.

Author ORCIDs

A. Baruzzi https://orcid.org/0009-0004-9171-7951

P. Mazzei https://orcid.org/0009-0006-5807-192X

Z. Zerunian https://orcid.org/0009-0002-2598-3931

Data availability

All of the data that support the findings of this study are available in the main text.