Life cycle of a new species of Duboscqia (Microsporida: Thelohaniidae) infecting the mosquito Anopheles hilli and an intermediate copepod host, Apocyclops dengizicus.

A new species of Microsporida, Duboscqia dengihilli, was found infecting larvae of the mosquito Anopheles hilli in northern Queensland, Australia. Laboratory experiments showed that binucleate spores formed within infected female mosquitoes were responsible for transovarial transmission to the next generation. Sporogony within the larval fat body was initiated by two diplokarya, one at each end of the cell, which undergo meiosis within a single sporophorous vesicle to form 16 meiospores. These spores are responsible for horizontal transmission to the copepod Apocyclops dengizicus. The microsporidium is transmitted back to the mosquito host via uninucleate pyriform spores formed within the copepod host which are infectious to larvae of A. hilli. The meronts within larvae infected by horizontal transmission ultimately develop into the binucleate spores within adult females to complete the life cycle. Thus, the development of this microsporidium involves vertical transmission between successive mosquito generations and horizontal transmission between mosquitoes and copepods similar to the life cycles of Amblyospora and Parathelohania.