Nosema (Microspordia: Nosematidae) infections associated with introduction of the European bumblebee in Japan
Maki Inoue, Takahiro Yanagisawa , Madoka Nakai , Maki Inoue
Tokyo University of Agriculture and Technology; Tokyo University of Agriculture and Technology ; Tokyo University of Agriculture and Technology ; Tokyo University of Agriculture and Technology
Bumblebees (Bombus spp.) are among the most important pollinators both for wild plants and agricultural crops. Now some bumblebees have been produced commercially and used for greenhouse pollination around the world. One of them, the European bumblebee, Bombus terrestris (L.), has been introduced into Japan since 1991. The species has widely established throughout a broad range of Hokkaido, northern Japan and caused the decline of native bumblebee species via competition for resources, cross-mating, and transfer of pathogens. The Microsporidia are obligate intracellular parasites that infect both vertebrate and invertebrate hosts. The Apidae family species harbour different microsporidia (Nosema) species, and Nosema bombi is known to be a microsporidian parasite of some bumblebee species including B. terrestris. In the United State, N. bombi is considered to be involved in the bumblebees’ declines. Under laboratory condition, N. bombi isolated from a commercial B. terrestris colony could infect two Japanese native bumblebees. Therefore, accompanied with B. terrestris invasions, N. bombi may spread among the Japanese bumblebee population, resulting in their declines. Here, we examined the prevalence and genetic variations using SSUrRNA region of Nosema spp. in both introduced and native bumblebee species in Japan, and characterized two Nosema spp..