Distribution of anopheline mosquitoes in northern Australia.

Using carbon-dioxide-baited light traps and larval sampling, anopheline mosquitoes were collected from 620 sites in northern Australia. Twelve species were recorded. Anopheles annulipes s. l. (335 sites). An. bancroftii (181 sites), An. meraukensis (162 sites), An. farauti s. s. (133 sites), An. farauti 3 (93 sites), An. amictus (93 sites), An. hilli (88 sites), An. novaguinensis (70 sites), and An. farauti 2 (67 sites) were common and widespread throughout the region, while An. powelli (5 sites), An. stigmaticus (2 sites), and An. colledgei (1 site) were rarely collected. At the time of the surveys the distribution of these species was not limited by the availability of oviposition sites.

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.

Life cycle of Amblyospora indicola (Microspora: Amblyosporidae), a parasite of the mosquito Culex sitiens and of Apocyclops sp. Copepods.

The life cycle of Amblyospora indicola, a parasite of the mosquito Culex sitiens, was revealed by field observations and laboratory infection experiments conducted in Australia. In northern Queensland, infected C. sitiens larvae were often found breeding in association with two cyclopoid copepods: Apocyclops dengizicus and an undescribed species of the same genus. The latter species was found to be an intermediate copepod host of this microsporidium whereas A. dengizicus was not. One complete cycle of the parasite extends over two mosquito generations (by transovarial transmission from females with binucleate spores to their eggs) and by horizontal transmission between mosquitoes and copepods. The latter involves horizontal transmission from mosquitoes to copepods via meiospores produced in larval fat body infections and horizontal transmission from copepods to mosquitoes via uninucleate spores produced within infected copepods. Uninucleate clavate spores were formed in Apocyclops sp. nov. copepods 7-10 days after exposure to larval meiospores and were infectious to larvae of a microsporidian-free colony of C. sitiens. The development of A. indicola within mosquito larvae exposed to infected copepods is similar to that of A. dyxenoides infecting C. annulirostris. It proceeds from stages with a single nucleus to diplokaryotic binucleate cells in oenocytes. These stages persist through pupation to adult emergence after which time a proportion of male mosquitoes and female mosquitoes may develop binucleate spores without the need for a blood meal. A proportion of both male and female larval progeny of infected females with binucleate spores develop patent fat body infections via transovarial transmission and die in the fourth larval instar.(ABSTRACT TRUNCATED AT 250 WORDS)

Light and electron microscope studies on three new species of microsporidia from saltmarsh mosquitoes in Australia.

Descriptions are given of three microsporidians found parasitising larvae of culicine mosquitoes in south-east Queensland, Australia. Two, Duboscqia aediphaga n.sp. and Microsporidium lotaensis n.sp. were recovered from larvae of Aedes (Ochlerotatus) vigilax (Skuse), and a third, Amblyospora pinensis n.sp., from Culex sitiens Wiedemann. The three species were studied by light microscopy and scanning and transmission electron microscopy. We believe this to be the first detailed account of the ultrastructure of a species of Duboscqia Perez.