Infectious intimacy and contaminated caves—three new species of ectoparasitic fungi (Ascomycota: Laboulbeniales) from blaniulid millipedes (Diplopoda: Julida) and inferences about their transmittal mechanisms

Laboulbeniales is an order of more than 2000 species of small ascomycete fungi which are ectoparasites of insects, millipedes and mites. They are often highly host-specific and often are also highly specific with regard to which body parts they infect. Laboulbeniales from millipedes are particularly poorly known—only 12 species have been described until now, mostly from Europe. Here, we describe the first laboulbeniaceous parasites from blaniulid millipedes: Troglomyces bilabiatus from Acipes spp., Troglomyces pusillus from Iberoiulus cavernicola Ceuca, 1967 and Troglomyces triandrus from Archiboreoiulus palidus (Brade-Birks, 1920). The generic description of Troglomyces is emended. Different types of site specificity of the three new parasites, as well as of previously described species, are explained in terms of aspects of host biology: mating behaviour and habitat. Species from epigean hosts tend to show a high degree of site specificity suggesting transfer during host copulation, whereas most species from cave hosts show no pronounced site specificity and are probably transferred via the substrate. Possible roles of host defensive secretions and parthenogenesis in relation to infection with Laboulbeniales are briefly discussed.