Diversity and species delimitation in Arthrorhynchus
Background
Laboulbeniales (Ascomycota) are obligate associates of arthropod hosts. Species in this order are microfungi that form three-dimensional fruiting bodies—named thalli—instead of mycelia and are associated with a living host for the entire duration of their life cycle. These microfungi, with about 2325 described species in 145 genera, form the most diverse fungal assemblage associated with representatives of the Phylum Arthropoda, predominantly insects. Laboulbeniales are a poorly studied group, with most research having focused on alpha taxonomy¾species descriptions based on morphology alone. Our research group studies tritrophic interactions that involve Laboulbeniales associated with bat flies (Diptera: Nycteribiidae and Streblidae), which are bloodsucking ectoparasites of bats (Mammalia: Chiroptera). Species of bat fly-associated Laboulbeniales are found in four genera, Arthrorhynchus, Dimeromyces, Gloeandromyces, and Nycteromyces.
Problems
The species diversity of bat fly-associated Laboulbeniales in the American tropics has been studied using an integrative taxonomy approach by our research group. Our work has revealed multiple undescribed species in the genera Gloeandromyces and Nycteromyces, as well as phylogenetic species with multiple morphotypes as a result of position-induced morphological plasticity in Gloeandromyces. While more work is needed, the Laboulbeniales on bat flies from the Eastern Hemisphere remain unstudied. A preliminary phylogenetic reconstruction of a small dataset with large subunit sequences of Arthrorhynchus shows that one species may be a species complex. Arthrorhynchus is a genus currently consisting of 4-5 species that are all poorly characterized or only known from a single collection.
Goals
The overall goal of this thesis project is to improve our knowledge of bat fly-associated Laboulbeniales in the Eastern Hemisphere. Our main focus will go to Arthrorhynchus but also other finds will be documented. Bat flies were collected during fieldwork in Croatia, Romania, Serbia, and Kenya and sent to Ghent University for this thesis project. Bat flies will be screened for the presence of Laboulbeniales. Infected specimens will be separated and assigned a unique label. The student will then perform morphological (permanent slide mounts) and molecular work (DNA extraction, PCR amplification of informative DNA regions, sequencing). Newly generated sequences will be supplemented with sequences available in public databases for building single-locus and multi-locus phylogenies. Morphology, phylogenies, sequence-based species delimitation methods, and ecological information (host association) will allow for an accurate overview of species diversity in Arthrorhynchus (studied material). The student will write up-to-date species descriptions of the known and potentially new species of Laboulbeniales following best practices.
The student will become familiar with a variety of research methods, including light microscopy, DNA extraction, PCR amplification, sequencing, phylogenetic approaches, species delimitation analyses, and integrative taxonomy. Pending approval from our local partners and funding, fieldwork will be possible during the summer of 2023 in Krka National Park, Croatia.
References
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Haelewaters D, Dick CW, Cocherán Pittí KP, Dittmar K, Patterson BD. 2021. Chapter 21. Bats, Bat Flies, and Fungi: Exploring Uncharted Waters. pp. 349-371. In: Lim BK, Fenton MB, Brigham RM, Mistry S, Kurta A, Gillam EH, Russell A, Ortega J (eds.) 50 Years of Bat Research. Fascinating Life Sciences. Springer, Cham. https://doi.org/10.1007/978-3-030-54727-1_21 [pdf]
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Haelewaters D, van Wielink P, van Zuijlen JW, Verbeken A, De Kesel A. 2012. New records of Laboulbeniales (Fungi, Ascomycota) for The Netherlands. Entomologische Berichten 72(3): 175-183. [pdf]
Liu J, Haelewaters D, Pfliegler WP, Page RA, Dick CW, Aime MC. 2020. A new species of Gloeandromyces from Ecuador and Panama revealed by morphology and phylogenetic reconstruction, with a discussion of secondary barcodes in Laboulbeniomycetes taxonomy. Mycologia 112(6): 1192-1202. https://doi.org/10.1080/00275514.2020.1781496 [pdf]
