Zygaena sedi Fabricius 1787 discovered and burned on Sakar Mts in Bulgaria

Received: 7 August 2025; accepted: 30 September 2025 · Editor: Kal Ivanov 343 Historia naturalis bulgarica 47 (11): 343–346 ISSN 2603-3186 (online) | ISSN 0205-3640 (print) · nmnhs.com/historia-naturalis-bulgarica https://doi.org/10.48027/hnb.47.111 Publication date [online]: 3 November 2025 Research article Zygaena sedi Fabricius 1787 discovered and burned on Sakar Mts in Bulgaria Ana Nahirnić-Beshkova1, Ivaylo Todorov2 (1) [Corresponding author] National Museum of Natural History, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000 Sofia, Bulgaria, [email protected] ✉; https://orcid.org/0000-0002-7922-9910 � (2) Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1 Tsar Osvoboditel Blvd, 1000 Sofia, Bulgaria, [email protected] ✉; https://orcid.org/0000-0002-2010-3395 � Abstract: Zygaena sedi sliwenensis Reiss, 1933 is a subspecies that only occurs in Bulgaria around Sliven Town, Karandila Place near the same town and Ivaylovgrad vicinity. The populations from Pirin Mts – Lilyanovo near Sandanski have not yet been assigned to a subspecies. Here we report the fifth locality of this species from Sakar Mts. The indication for the host plant being Vicia is discussed. The influence of a wildfire on the habitat is commented. Keywords: Eastern Bulgaria, Vicia, wildfire, Zygaena sedi sliwenensis Introduction Zygaena sedi Fabricius, 1787 is a Ponto-Mediterranean and Ponto-Caspian species with a very local and disjunct distribution. It is distributed in the following seven areas: Albania – Greece, Lilyanovo in Southwestern Bulgaria, Sliven and Ivaylovgrad in Eastern Bulgaria, Crimea, the Lower Volga, Southern Urals, and Turkey (Hofmann & Tremewan, 2020). Zygaena sedi sliwenensis Reiss, 1933 is an endemic subspecies for Bulgaria, currently reported from its type locality Sliven, as well as in Karandila near Sliven and Ivaylovgrad Town vicinity. The subspecific affiliation of Z. sedi from Lilyanovo is unclear. The nominotypical subspecies is distributed in the Middle and Southern Volga region in Russia. Zygaena sedi dellabrunai (Dujardin, 1981) is found in Albania and Greece, while Z. sedi roxana Naumann & Naumann, 1980 occurs in Central and Eastern Turkey (Hofmann & Tremewan, 2020). Zygaena sedi cimmerica Efetov, 2018 is restricted to Crimea (Efetov, 2018). The most recent records from Bulgarian localities are from Sliven in 1962 (Naumann & Naumann, 1980), Karandila in 1965 (de Freina & Witt, 2001), Lilyanovo in 1984 and 1985 (de Freina & Witt, 2001; Hofmann & Tremewan, 2020) and Ivaylovgrad in 2023 (Essayan & Jugan, 2025). Astragalus sirinicus Ten. is reported as a host plant in Greece (Hofmann & Tremewan, 2020), while Vicia cracca L. is reported for Turkey (Hofmann & Tremewan, 2020), and Vicia tenuifolia Roth (V. dalmatica Kerner, V. elegans auct. non Guss.) (Fabaceae) is reported for Crimea (Efetov, 2018). Hofmann & Tremewan (2020: 554) write that “Becker (1888: 375; 1892a: [2]; 1892b: 65) recorded ʻVicia branchytropis’ as the larval host plant in Sarepta (Krasnoarmeysk), but we have been unable to trace any reference to a plant of this name in the botanical literature.” We found that Vicia brachytropis Kar. & Kir. is a synonym of Vicia tenuifolia Roth. There is only one study on Zygaenidae from the Sakar Mts conducted by Nahirnić et al. (2021) during two field trips in 2019, in which 13 species from nine localities were reported. As Sakar Mts has a wide variety of different habitat types and is promising for the occurrence of other species, field studies were also carried out in 2023–2025. Ana Nahirnić-Beshkova, Ivaylo Todorov 344 Historia naturalis bulgarica 47 (2025) Materials and methods As Bulgaria lies between Albania and Greece on one side, where the host plants of Z. sedi are Astracantha spp., and Crimea and Turkey on the other side, where its host plants are Vicia spp., we inspected several localities in eastern Bulgaria with abundant spiny Astracantha spp. (Astracantha thracica (Griseb.) Podlech, Astracantha arnacantha subsp. aitosensis (Ivan.) Réer & Podlech and Astragalus angustifolius Rohlena), and Vicia tenuifolia Roth. The surroundings of Lilyanovo were also inspected but none of the potential host plants were found. Several meadows with abundant V. tenuifolia were inspected in the west of Ivaylovgrad where the species was found in 2023. Results A single female was found on 21 June 2023 by I. Todorov at Sakar Mts near Shtit Village at an altitude of about 200–300 m. On 1 June 2024, A. NahirnićBeshkova visited the same place and ca. about 150 m away. After 10 minutes of observation, a female of Z. sedi flew out of the V. tenuifolia clump. An area of about six square kilometres around this patch was searched for host plants, but neither Vicia nor Astracantha was found. On 8 June 2025, two specimens, a female and a male, were found in the west of Ivaylovgrad at an altitude of about 500–600 m, in a meadow with abundant V. tenuifolia and V. villosa Roth. Vicia grandiflora Scop. was present but much less abundant. The female was nectaring on V. tenuifolia. Discussion Our two specimens from Sakar Mts (Fig. 1a), and the two specimens found west of Ivaylovgrad (Fig. 1b), correspond to Z. sedi sliwenensis, which has mainly confluent forewing spots with extended white surroundings. Two specimens from the type locality, deposited in the National Museum of Natural History in Sofia, are illustrated for comparison (Fig. 1c–d). Although no dates are given on the label of the specimens collected by J. Haberhauer in Sliven, Buresch & Tuleschkow (1943) wrote that they were collected in a year 1895. Date of collection of several specimens labelled: “Collectio Princ. Bulg. Slivno.” remains unknown, but they most likely originate from the end of the 19th century to the first half of the 20th century. Fig. 1. Females of Zygaena sedi from Bulgaria. a – Sakar Mts, 1 June 2024; b – in the West of Ivaylovgrad, 8 June 2025; c – Sliven, coll. Prince of Bulgaria; d – Sliven, 1895, coll. Haberhauer. Scale = 1 cm. Zygaena sedi Fabricius 1787 discovered and burned on Sakar Mts in Bulgaria 345Historia naturalis bulgarica 47 (2025) As we found one specimen that flew from a V. tenuifolia clump, and two others were found in a meadow with abundant V. tenuifolia, and Essayan & Jugan (2025) reported Z. sedi near Ivaylovgrad in fields covered with “Vicia cracca (ssp. locale) ou de Vicia elegans”, which we interpret as V. villosa and V. tenuifolia, respectively, we have reason to believe that V. tenuifolia is its host plant in eastern and Southeastern Bulgaria. The host plant in Lilyanovo remains unknown. The place where Z. sedi was found on 1 June 2024 is a patch ca. 22 m2 covered with V. tenuifolia clumps, and nearby there was another patch of 12 m2 covered with V. villosa (Fig. 2a). On 8 July 2024 we revisited the site and more than 90 % of V. tenuifolia was dry (Fig. 2b). The entire area has been burned in a large wildfire that covered over 100,000 ha on Sakar Mts on 13–15 July 2024. We visited the locality on 11 October 2024 to check if the exact place was burned (Fig. 2c). The impact of fire on the population of some species of Lepidoptera may depend on several factors. In this case, the entire patch with the only host plant was burned. Since we know that the host plant was almost completely dried only 5 days before the fire, it is possible that the young larvae have already gone into aestivation. This was a slightly better scenario, as the larvae were hidden in the litter and not feeding on the host plant. Since the patch with the host plant was already small before the fire, it is possible that the loss of both the host plant and the young larvae was large enough to prevent the population from recovering. On 5 June 2025, during the full bloom of V. tenuifolia, the site was visited again. Vicia tenuifolia has been comFig. 2. The exact place where Z. sedi was collected in the Shtit Village vicinity. a – 1 June 2024, b – dry Vicia tenuifolia on 8 July 2024, c – 11 October 2024, d – 5 June 2025. Ana Nahirnić-Beshkova, Ivaylo Todorov 346 Historia naturalis bulgarica 47 (2025) pletely recovered, although some clumps were not flowering (Fig. 2d). Zygaena sedi was not found, although this time of the flowering period of V. tenuifolia is optimal for its flight. It is still too early to determine whether it is extinct at this locality, but this is very likely. There is no doubt that the newly rediscovered species requires conservation measures. Zygaena sedi is of considerable interest to Lepidoptera collectioners (Nahirnić-Beshkova, pers. obs.; S. Beshkov, pers. comm.), which is another threat to this species. We consider that Z. sedi should be included in the list of protected species in Bulgaria, and that the localities where it occurs should be placed under a protection regime. Acknowledgements We are thankful to Stoyan Beshkov for his assistance during the fieldwork, and to Chavdar Gussev for the determination of the species of Vicia. Financial support for this study was provided by the grant KP-06N51/1-18.08.2022 (Biodiversity of target insect groups (Coleoptera, Hymenoptera and Lepidoptera) and their pathogens from different habitats in Bulgaria), funded by the Bulgarian National Science Fund of the Ministry of Education and Science of Bulgaria. Conflicts of interest No potential conflict of interest has been reported by the authors, reviewers, or subject editor. References Buresch I., Tuleschkow K. 1943 Die horizontale Verbreitung der Schmetterlinge (Lepidoptera) in Bulgarien V. Mitteilungen aus den Königlichen Naturwissenschaftlichen Instituten in Sofia 16: 79–188. (In Bulgarian) Freina J.J. de, Witt T.J. 2001 Die Bombyces und Sphinges der Westpalaearktis. (Insecta, Lepidoptera). Band 3 Zygaenoidea: Zygaenidae. 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