Diurnal Butterfly Species Visiting Chamaecytisus heuffelii (Wierzb.) Rothm. Flowers in SW Hungary Imre Fazekas Citation. Fazekas I. 2024: Diurnal Butterfly Species Visiting Chamaecytisus heuffelii (Wierzb.) Rothm. Flowers in SW Hungary. – Lepidopterologica Hungarica 20(2): 11–16. https://doi.org/10.5281/zenodo.14138715 Abstract. This study investigated one of the rarest plants in Hungary, Chamaecytisus heuffelii (Wierzb.) Rothm. [Fabaceae] in terms of the butterfly species that visit flowers as a nectar source. It also provides a general overview of the plant, its habitat, and geographical distribution. Chamaecytisus heuffelii is a highly endangered species in Hungary that may soon become extinct here. The flower-visiting butterfly species showed gradual regression. These numbers are decreasing annually. This was not caused only by habitat degradation; the main cause is probably that the area has been sprayed with chemicals for many years to control mosquitoes. The spraying was stopped a few years ago. Keywords. Hungary, butterflies, flower visits, Chamaecytisus heuffelii , conservation, biodiversity Author’s address. Imre Fazekas | Pannon Institute | H-7625 Pécs Magaslati út 24. E-mail: fazekas@outlook.com | https://orcid.org/0000-0003-4318-3946 Introduction Chamaecytisus heuffelii is a perennial semi-shrub with a distribution confined to the Balkan re- gion. In Hungary it is found only in the city of Pécs, where it is located within a protected rocky site. This site is likely to be the northernmost and westernmost location where the spe- cies is known to occur. As such, Chamaecytisus heuffelii is a distinctive component of Hungar- ian flora, and its conservation in its native habitat is of considerable importance for nature con- servation, both in Hungary and internationally. The expansion of Pécs, involving construction, tourism growth, and grassland degradation, presents the primary threat to its habitat. This plant, safeguarded by the Hungarian Nature Con- servation Act of 2005, is reported to be under threat of extinction, as indicated by the Hungari- an Red List (Király 2007). The Havi Hill in Pécs, Hungary, is the sole location where the following formations can be found: coarse limestone and lime sandstone. This type of rock is representative of the Sarmati- an floor of the Miocene. The remains of calcareous marine organisms that perished and were deposited in the shallow Sarmatian Sea, which bordered the coast 12–14 million years ago, re- sulted in the formation of this rock (Kraft 2000, Lehmann 2009). The height of the hill was 170 –246 metres above the sea level. The hill and its surroundings have been affected by quarrying for generations, although mining operations on Havi Hill ceased in the 1950s. The city of Pécs designated this area as a nature reserve of local importance. However, this area has been managed negligently for some years. In some cases, people have cut the entire grassland with a lawnmower, oblivious to the value of the protected plants. Not only the vege- tation but also the ground fauna suffered considerable damage. To date, city authorities have not named or held accountable those responsible for this damage. This plant's habitat is expected to have been checked continuously between 2005 and 2024. I am mainly interested in the species of butterflies that visit during the flowering period. First, I will briefly describe the habitat and geographical distribution of Chamaecytisus heuffelii, fol- lowed by an overview of the flower-visiting butterfly species. Lepidopterologica Hungarica 20(2): 11–16. | ISSN 2732-3498 (online) ISSN 2732-3854 (print) 11 Received 03.07.2024 | Revised 30.06.2024 | Accepted 10.07.2024 | Published: 13.11.2024 (online) https://epa.oszk.hu/04100/04144 https://doi.org/10.5281/zenodo.14138715