Ultrastructure and tissue pathology of two microsporidia infecting the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae) and the green lacewing Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), used for biological control

Abstract

Two undescribed microsporidia were found in insects that are commercially available for biological control: one from field-collected Adaliae bipunctata and another from Chrysoperla carnea purchased from a commercial insectary. The objective of this study was to describe both microsporidian pathogens by means of their ultrastructure, tissue pathology and ribosomal RNA gene sequences (molecular characterization). Both microsporidia were closely related to several species within the genus Nosema and were given the names Nosema adaliae sp. nov. and Nosema chrysoperlae sp. nov., respectively. Spores of N. adaliae measured 4.25 ± 0.09 x 1.82 ± 0.03 [micrometres] and had an isofilar polar filament with 10-18 coils. Various host tissues were infected, including the fat body, muscles, ovaries, testes, midgut, hindgut and ventral nerve cord. Spores of N. chrysoperlae measured 3.49 ± 0.10 x 1.52 ± 0.05 [micrometres] and had an isofilar polar filament with 8-10 coils. The majority of host tissues were infected except for the ovaries.