AUTHOR=Van Caenegem Warre , Ceryngier Piotr , Romanowski Jerzy , Pfister Donald H. , Haelewaters Danny 

TITLE=Hesperomyces (Fungi, Ascomycota) associated with Hyperaspis ladybirds (Coleoptera, Coccinellidae): Rethinking host specificity

JOURNAL=Frontiers in Fungal Biology

VOLUME=3

YEAR=2023

URL=https://www.frontiersin.org/journals/fungal-biology/articles/10.3389/ffunb.2022.1040102

DOI=10.3389/ffunb.2022.1040102

ISSN=2673-6128

ABSTRACT=<p>Laboulbeniales (Ascomycota, Laboulbeniomycetes) are biotrophic microfungi always attached to the exoskeleton of their arthropod hosts. They do not form hyphae or a mycelium; instead, they undergo determinate growth, developing from a two-celled ascospore to form a multicellular thallus. <italic>Hesperomyces virescens</italic> has been reported on over 30 species of ladybirds (Coleoptera, Coccinellidae); in reality, it represents a complex of species, presumably segregated by host genus association. In this study, we report on <italic>Hesperomyces</italic> thalli on <italic>Hyperaspis vinciguerrae</italic> from the Canary Islands and compare them with the <italic>Hesperomyces hyperaspidis</italic> described on <italic>Hyperaspis</italic> sp. from Trinidad. We generated the sequences of the internal transcribed spacer (ITS) region, the large subunit (LSU) nuclear ribosomal RNA gene, and the minichromosome maintenance complex component 7 (<italic>MCM7</italic>) protein-coding gene. Our phylogenetic reconstruction of <italic>Hesperomyces</italic> based on a concatenated ITS–LSU–<italic>MCM7</italic> dataset revealed <italic>Hesperomyces</italic> sp. ex <italic>Hy. vinciguerrae</italic> as a member of the <italic>He. virescens</italic> species complex distinct from <italic>He. virescens sensu stricto</italic> (s.s.). It also revealed that the <italic>Hesperomyces</italic> sp. ex <italic>Chilocorus bipustulatus</italic> from Algeria is different from <italic>He. virescens</italic> s.s., which is associated with <italic>Chilocorus stigma</italic> from the USA. This suggests that the species of <italic>Hesperomyces</italic> are not solely segregated by host association, but that there is also a biogeographical component involved. Based on these data, we refrained from referring our material from <italic>Hy. vinciguerrae</italic> to <italic>He. hyperaspidis</italic>. Finally, we discuss the usefulness of <italic>MCM7</italic> as a useful marker for species delimitation in <italic>Hesperomyces</italic>.</p>