The prevalence of obligate parasitic fungi may depend partly on the environmental conditions prevailing in the habitats of their hosts. Ectoparasitic fungi of the order Laboulbeniales (Ascomycetes) infect arthropods and form thalli on the host's body surface. Although several studies report the incidence of infection of certain host species by these fungi, quantitative data on laboulbenialean fungus-host arthropod interactions at the host assemblage level are rarely reported. To clarify the effects of host habitats on infection by ectoparasitic fungi, the incidence of infection by fungi of the genus Laboulbenia (Laboulbeniales) of overwintering carabid beetles (Coleoptera: Carabidae) in three habitats, a riverside (reeds and vines), a secondary forest and farmland (rice and vegetable fields), were compared in central Japan. Of the 531 adults of 53 carabid species (nine subfamilies) collected in the three habitats, a Laboulbenia infection of one, five and one species of the carabid subfamilies Pterostichinae, Harpalinae and Callistinae, respectively, was detected. Three species of fungus were identified: L. coneglanensis, L. pseudomasei and L. fasciculate. The incidence of infection by Laboulbenia was higher in the riverside habitat (8.97% of individuals; 14/156) than in the forest (0.93%; 2/214) and farmland (0%; 0/161) habitats. Furthermore, the incidence of infection by Laboulbenia in the riverside habitat ranged from 0 to 33.3% and differed significantly in the ten microhabitats (riverbank, edge of track, tall reeds, kudzu vines, slope of a hollow, rotten wood, vine reeds, under stones, the shoulder of a terrace and marshy ground) where the carabid beetles overwintered. These results suggest that host habitats and microhabitats are closely associated with successful infection by laboulbenialean fungi.
Vřecko představuje důmyslnou strukturu, kterou nacházíme pouze u vřeckovýtrusných hub. Po pohlavním procesu v něm vznikají askospory sloužící k šíření houby. Významná je funkce vřecka v aktivním rozšiřování askospor. Na odstřelování askospor se podílí stěna vřecka, vrcholový aparát a další buňky v hymeniu. V průběhu evoluce došlo u různých skupin vřeckovýtrusých hub k modifikacím ultrastruktury vřecka a jeho funkce v rozšiřování askospor., Ascus is a sophisticated structure that can only be found in Ascomycota. Ascospores formed in ascus after the sexual process are used for fungal dispersal. Ascus is very important for active discharge of spores. The ascus wall, apical apparatus and other hyphal elements in hymenium are involved in the shooting of spores. The ultrastructure and function of the ascus in the spores discharge has been modified during evolution of various groups of ascomycetes., and Ondřej Koukol.