Laboulbenialean fungi (Laboulbeniales, Ascomycota, Fungi) are microscopic superficial parasites of arthropods. The Laboulbeniales are a group of insect-associated fungi with a relatively strong specialisation, with 145 genera and about 3000 species described (Thaxter, 1926; 1931, Tavares, 1985, et al.), but current estimates suggest that there are at least 40,000 species awaiting description (Haelewaters et al., 2020; Kirk, 2019; Weir & Hammond, 1997). The effects of Laboulbeniales fungi on their insect hosts are not fully understood and there is still very little research on their ecology and biology (Haelewaters et al., 2021). Only a small number of countries have ongoing research on Laboulbeniales, but the diversity and uniqueness of this group of fungi undoubtedly makes it a source of new taxonomic and ecological information. The taxonomic characters of Laboulbeniales are based on the structure of the fruiting body, i.e. the visible part of the fungus outside the host. The attachment of the fungus through haustoria and its spread within the host remains largely unknown, but it has been established that some Laboulbeniales species have a haustorial structure that penetrates the cuticle of the host, while others  only attach  to the cuticle of the host, but do not penetrate it, and it is not clear what nutrients they use for their own growth ( Reboleira et al., 2021). The first major comprehensive taxonomical work on Laboulbeniales, which resulted in a 6-volume monograph, was carried out in the Americas by Roland Thaxter (Thaxter, 1926-1932). Among European countries, more detailed studies on Laboulbeniales have been carried out in Italy (Rossi, 1978; 1979), Spain (Santamaria, 2020; 2001) and Poland (Majewski, 1994; 2008). The first studies in neighbouring Latvia (Briedis, 1932) and in Lithuania were carried out almost 100 years ago (Siemaszko and Siemaszko, 1928; 1932). During the last decade, the Belgian entomologist De Kesel (2006) found, described and published several new species in Latvia. This ecologically interesting group of fungi has hardly been studied in Lithuania, and there is very little data on the diversity, distribution and ecology of Laboulbenialean fungi – only two papers have been published (Markovskaja, 2000; 2006). Biodiversity research will undoubtedly have to include taxonomic studies, as there is a high probability of discovering new species. Scientists currently studying Laboulbeniales in Belgium, Spain and Italy are more involved in diversity, ecology and taxonomy research and are in close contact with each other, organising joint expeditions and hosting interns. This international collaboration has resulted in several papers on Laboulbeniales from Bulgaria, Hungary, Czech Republic, Slovakia and other countries (Pfliegler et al., 2016; Rossi et al., 2019; Rossi & Santamaria, 2020).
The research to be carried out in the dissertation
Field surveys: collection of material (arthropod insects) in different regions and habitats of Lithuania. Laboratory studies: selection of infected insects using a stereomicroscope, removal of fungi from the insect and production of permanent preparations, identification of insects and fungi using light microscopy.
Inspection of existing entomological collections at the VU, GTC, and Tadas Ivanauskas Zoological Museum in Kaunas, as well as of amber collections with insect inclusions, to look for infected insect specimens with Laboulbeniales fungi. Close cooperation and consultations with entomologists in Lithuania and abroad. Internship abroad with one of the best Laboulbenialean fungi specialists ( W. Rossi / S. Santamaria or other).
Most fungi in this group are highly specialised and through a long coevolutionary process adapt to parasitise a particular insect species or genus. Correct identification of Laboulbeniales depends primarily on correct host identification. The identification of insects will require entomological knowledge, which will need to be developed.
Taxonomic and ecological analysis of the collected material, determination of the distribution and host specificity of the insects, clarification of the trophic relationship between host and parasite. Use of molecular methods for the identification of new species and morphologically similar species, phylogenetic analysis. Preparation and publication of taxonomic and ecological papers. Preparation of an illustrated synopsis with species descriptions.