Updates to the sporadic knowledge on microsporidian infections in groundwater amphipods (Crustacea, Amphipoda, Niphargidae)

Abstract

A set of 69 specimens from 19 groundwater species of the genera Niphargus, Niphargellus, Microniphargus and Crangonyx was genetically screened for microsporidian infections. Samples mostly originated from groundwater-dependent spring environments (71%), natural caves (9%) and artificial caverns/tunnels (13%). Amphipod hosts were identified by morphology and/or molecular data, whereas microsporidian parasites were characterised by a genetic screening assay targeting a section of the small subunit rRNA gene. Five microsporidian species (Dictyocoela duebenum; Nosema sp.; Hyperspora aquatica and two undescribed Microsporidium spp.) were revealed from 13 host specimens (Niphargus schellenbergi; N. aquilex lineages B, F and G; Niphargellus arndti). In particular N. schellenbergi was frequently infected with D. duebenum as well as a new and potentially niphargid-specific Nosema sp. identified in Niphargellus arndti. Our results shed further light on the still largely unknown diversity and specificity of microsporidian parasites in groundwater amphipods and subterranean animals in general.