Twenty-five-year mapping species of the superfamily Cercopoidea (Hemiptera, Auchenorrhyncha) in Bulgaria

Abstract Background In Bulgaria, the superfamily Cercopoidea consists of 18 species in two families - Aphrophoridae and Cercopidae. Of these, 13 species of Aphrophoridae belong to the genera Philaenus, Neophilaenus, Aphrophora and Lepyronia and five species of Cercopidae are in Cercopis and Haematoloma. Over a period of 25 years of extensive research on the species of the superfamily in the country, a large amount of geo-referenced data has been collected on 17 of the species, which has significantly increased knowledge of their biogeography. New information The paper presents a dataset of the materials of the superfamily Cercopoidea deposited in the Zoological Collection of the University of Sofia (BFUS). The specimens were collected from 888 localities in Bulgaria over a period of 25 years (1997 to 2022). The Cercopoidea collection comprises 8722 specimens grouped into 6670 collection objects. The text provides data for each species, including a distribution map, regional literature taxon names and identifiers from eight taxonomic infrastructures (GBIF, BOLD, OpenBiodiv, BHL, COL, Plazi, EOL and TaxonWorks). It also includes data from literature and new records, phenology and altitudinal distribution in Bulgaria, as well as known host plants. Live photographs are provided for all species. A nanopublication presents the establishment of a new host plant, Asphodelinelutea (L.) Rchb., for the species Philaenussignatus Melichar, 1896.


Introduction
The superfamily Cercopoidea (Hemiptera, Auchenorrhyncha), commonly known as spittlebugs, feed on xylem sap from a variety of plant hosts.Although some are monophagous throughout their lives or only in the nymphal stage, others are known to be very broadly polyphagous as Philaenus spumarius (L.) is known to be the most polyphagous phytophage (Thompson et al. 2023).Their colloquial name derives from the distinctive developmental pattern in their nymphal stages, which is characterised by the production of froth or "spittle", presumably as a protective covering.This foam, which is unique to insect nymphs, is produced when nymphs expel excess fluid mixed with products from the Malpighian tubes and possibly the abdominal epidermal Batelli glands through their anal opening while drawing in air, resulting in a foamy emulsion (Weaver andKing 1954, Rakitov 2002).During the entire pre-imaginal stage, the froth maintains a moist consistency, resembling spittle deposited upon the foliage (Weaver and King 1954).
The objective of this study is to present the results of a 25-year (1997 to 2022) sampling of Cercopoidea species in Bulgaria.The data presented in this study serve as a comprehensive reference for future research and monitoring.The dataset is published in GBIF and is open access, compliant with FAIR principles.

Materials and methods
The materials used in this study consist of 8722 specimens, which are organised into 6670 collection objects, each with a unique identification number.These specimens were collected from 888 localities in Bulgaria between 1997 and 2022 and are deposited in the Zoological Collection of the University of Sofia (BFUS).They were sampled by the authors in a variety of locations across the country, with varying levels of intensity and effort.Some localities were visited on multiple occasions.
The specimens were collected using a sweeping net and subsequently extracted with an aspirator.Ethyl acetate vapour was used to kill the specimens.To preserve them for longterm storage, they were placed on layers of cotton.The majority of the specimens were pinned on to glue boards.In cases where there were too many, they were separated by sex, counted and placed in entomological pin-mounted gelatin capsules and polypropylene tubes.The genital apparatus of the male specimens was dissected to observe their identifying characteristics.The material was identified by referring to the latest literature (Drosopoulos and Asche 2000, Drosopoulos and Remane 2000, Drosopoulos 2003, Biedermann and Niedringhaus 2009) and databased using Specify 7 Collection software.The software generated three labels for each collection item: 1. collection event data; 2. determination; 3. individual collection object number and QR code.The labels were cut using a cutting plotter, mounted on to the pins of the collection objects by using of a 3D pinning block (Gjonov 2022, Gjonov andHristozov 2024).Distribution maps were created using the free and open source programme QGIS 3.28 (http://www.qgis.org)and MapTiler shapefile (https://www.maptiler.com/).
The species accounts include distribution maps, identifiers from eight taxonomic infrastructures (GBIF, BOLD, OpenBiodiv, BHL, COL, Plazi, EOL and TaxonWorks), regional literature taxon names (chresonymy), as well as literature and new records, phenology, altitudinal distribution in Bulgaria and known host plants.Live photographs are also included for all species.Unless otherwise indicated, the images presented are of specimens collected from Bulgaria.For some species, additional notes on habitat and frequency of occurrence are included.
The finding of a new host plant for Philaenus signatus Melichar, 1896 was presented as a nanopublication.
Additional notes: Common in Bulgaria.
Host plant: Nymphs on various plants in the understorey of pine saplings, adults on Pinus sylvestris L. (Nickel 2003).
Additional notes: Rare in Bulgaria.
Additional notes: Common in river valleys.
Additional notes: Common species.
Additional notes: Rare in Bulgaria.

Additional notes:
In Bulgaria, it occurs mainly in the high parts of the mountains.
Literature data: Sofia Plain (Bajrjamova 1990); Vitosha Mts.(Nedjalkov 1908) .Both records are uncertain as the recorded locations do not match the ecological requirements of the species.

Host plant:
In Greece, adults of the species have been collected on various shrubs and trees, especially those of the genera Arbutus and Quercus ( Drosopoulos and Asche 2000).As of now, the only recorded plant of the nymph and the freshly emerged adults is Asphodelus microcarpus Parl (Asphodelaceae) ( Drosopoulos 2003).In Bulgaria, during the early summer, it was collected on a new host plant of Asphodeline lutea (L.) Rchb.(Asphodelaceae).Later in the season, when the plant's ground mass had wilted, it moved as adults on to woody species of the genus Quercus.
Additional notes: In Greece, it usually lives in the same habitat as Philaenus spumarius, more often near the sea, but there are also isolated records from the mountains (Drosopoulos and Asche 2000).In Bulgaria, it has been collected along the southern Black Sea coast and there are also isolated records in the mountains, near the border with Greece.Colour polymorphism is observed.Rare in Bulgaria.
Common in Bulgaria.
Host plant: Pine or oak forests, with the majority of adults discovered amongst dicotyledonous herbs in the Czech Republic, Austria and France (Nickel 2003).
Host plant: Adults polyphagous on various tall herbs and grasses, Nymphs subterranean on Poaceae roots (Nickel 2003).
Additional notes: Rare in Bulgaria.

Discussion
Bulgaria  Most species are broad oligophagous or polyphagous, with the exception of Aphrophora corticea, which is monophagous on pines and Philaenus signatus, whose nymphs and freshly-emerged adults are known to be monophagous on Asphodelus microcarpus.A new food plant, Asphodeline lutea, has been established for the species in Bulgaria in the current study.
The 25-year study of Cercopoidea in Bulgaria has yielded 8722 digitised specimens from 888 locations.These data could be a valuable reference for future research and monitoring.
; Sakar-Tundzhan Region(Dlabola 1957).New data: Pre-Balkan; Western, Central and Eastern Stara Planina Mts.; has a relatively rich species diversity of the superfamily Cercopoidea in Europe due to the Bulgarian geographical location and varied topography, which provide conditions for different habitats.Out of 38 species known for Europe, 16 species have been recorded for the country and one species, Haematoloma dorsatum, is in need of confirmation.The majority of species in Bulgaria have a wide distribution and can be found at various altitudes.However, certain species, such as Aphrophora corticea, Neophilaenus exclamationis and Cercopis vulnerata, are only found in a few localities and the distribution of Neophilaenus infumatus is restricted to the high mountains of Bulgaria.