Parasitism of ladybirds by Hesperomyces in the Canary Islands

Between 2016 and 2022, the ladybird (Coleoptera: Coccinellidae) fauna was surveyed on seven main islands of the Canary Islands archipelago. Adult specimens were collected and screened for thalli of Laboulbeniales (Ascomycota: Laboulbeniomycetes). Altogether, 9,807 ladybird specimens belonging to 39 species were screened, of which 103, representing 10 species, were infected by Laboulbeniales of the genus Hesperomyces. Morphological and molecular examination allowed to distinguish at least seven host-specific Hesperomyces species belonging to three groups: He. virescens species complex (associated with Adalia decempunctata, Harmonia axyridis, Hyperaspis vinciguerrae, Novius cruentatus, Parexochomus nigripennis, and P. quadriplagiatus), He. coccinelloides species complex (Scymnus nubilus, Sc. subvillosus durantae, and Stethorus tenerifensis), and a species (on Nephus flavopictus) that cannot be assigned to either of the above species complexes or the currently described species in the genus. The most widespread and abundant species was Hesperomyces ex St. tenerifensis; it was recorded on all seven islands with prevalence rates ranging between 0.04 and 0.19.