Ábrahám Levente – Farkas Sándor: Butterflies along the river Drava, 2008

The most frequent purple emperor species is the lesser purple emperor (Apatura ilia) [l]. The cross-bands on their bluish-iridescent wings are redishbrown, but sometimes one might encounter white banded specimens as well. There is no dentate protuberance in the discal band of their hindwings. In areas along Drava, two generations develop during one year. Lesser purple emperors fly in early summer and late summer. Although with lesser numbers, sometimes there are single-generation (univoltin) populations too, which tend to fly in mid summer. The purple emperor (Âpatura iris) [2] is a typical species of montane areas. It is observed along Drava only occasionally. Its caterpillars develop on sallow willow, in the edge of forests with cool microclimate. The cross-bands of the wings are always white, and the protuberance on the cross-band of hindwings is clearly observable. This species flies in the middle of summer. The most valuable butterfly species of the Drava region is Freyer's purple emperor (Apatura metis) [3j. Its populations are found in habitats directly at the rivershore. There is a strong protuberance on the rust-brown cross-band of the hindwings. Two generations develop during a year. Male specimens are often encountered in groups, licking on the moist sediment of the riverbed, but the females only rarely descend from the forest canopy It is a Natura 2000 species, enjoying special protection in the European Union.