Ovavesicula popilliae (Microsporidia: Ovavesiculidae) spore production in naturally infected adult Japanese beetles (Coleoptera: Scarabaeidae)

[Display omitted] . ► We estimated spore production of Ovavesicula popilliae in P. japonica. ► Mean spore production per adult Japanese beetle was 2.67×107 (SE±4.65×106). ► Spore load may help explain the spread from introduction sites to surrounding areas. Ovavesicula popilliae is a microsporidian that infects both Japanese beetle larvae and adults. This is the first study quantifying the number of O. popilliae spores produced by Japanese beetle adults. Mean spore production per adult Japanese beetle was 2.67×107 (SE±4.65×106) spores with a range of 1.46×106–1.02×108. The number of spores produced per host is similar to other microsporidian species and may help explain the speed with which this pathogen has spread from introduction sites to surrounding areas.