Southern swallowtail
Southern swallowtail(Papilio alexanor, [1800]) is one of the most charismatic diurnal butterflies in Croatia. It is one of seven easily recognizable and large diurnal butterflies of the swallowtail family (Papilionidae) in Croatia, characterized by an imago wingspan of 55 to 70 mm and females that are usually larger than males. The imago is easily recognized as it takes the form of two almost vertical lines in the central section of the front part of the wing. The actual geographical distribution of the species in Croatia was unknown and unexplored for decades, and, until recent systematic multi-year research, it was considered extremely rare and known only from a few historical localities in Istria, Krk and Dalmatia. The southern swallowtail is rarely seen due to its remote and inaccessible habitats on steep rocky limestone slopes and south-facing cliffs. Today, it is known that the species is widespread in several localities in Dalmatia, south of Split, where its imago can be seen flying along the rocks and next to the woolly thistle (Cirsium eriophorum) and the bird vetch (Vicia cracca). Due to the highly fragmented Euro-Central Asian distribution area, caterpillar host plants differ in certain areas of Europe. This is probably due to the ecological needs of the caterpillar host plants, some of which are pioneer species that select eroded and poor soils. Research has shown that the swallowtail populations have a preference for one type of umbellifers, and, due to different flowering times, they can use up to three types. In Italy and France, the species' caterpillar feeds on the seeds and flowers of Ptychotis saxifraga, Hercules' all-heal (Opopanax chironium), Seseli montanum and honewort (Trinia glauca), in Greece it feeds on Hercules' all-heal (Opopanax chironium), species of the Pimpinella genus and species of the Ferulago genus, whereas in Croatia it only eats Hercules' all-heal (Opopanax chironium). The caterpillar is similar to the caterpillar of the southern swallowtail with a chartreuse ground color and transverse black and red stripes on its back. The southern swallowtail hibernates in the pupal stage. It creates one generation per year, and its imago appears between the beginning of April and the end of July. The southern swallowtail is endangered due to a lack of favorable O. chironium habitats in which it grows in abundance, as they are under great pressure of urbanization and serious fragmentation. The main threat to its survival is the destruction of favorable habitats along the edges of roads and slopes, potential illegal collecting, and the constant reduction of populations due to the local disappearance/extinction of the species in historically known locations. The species is protected by the Nature Protection Act in the category of strictly protected native wild taxa, so collecting adult speciemen of the species, as well as specimen in the caterpillar stage, is illegal. The species can be found in Appendix IV of the Directive on the conservation of natural habitats and of wild fauna and flora (Council Directive 92/43/EEC) and Appendix II of the Berne Convention, and it is considered extremely sensitive to climate change as a species of extremely high risk of categorization in the Climate Risk Atlas of European Butterflies.
