Culex molestus Forskal (Diptera: Culicidae) in Australia: colonisation, stenogamy, autogeny, oviposition and larval development

Mosquito borne-disease is of increasing concern for public health authorities. The Culex pipiens subgroup of mosquitoes includes some of the most important vector species internationally and four species within this subgroup are found in Australia. Culex molestus (Forskal) is one of these species, is thought to have been introduced into Australia in the 1950s and is closely associated with subterranean urban environments. Concern has been raised as to the potential role this species may play in the transmission of important exotic and endemic arboviruses. An understanding of the biology and ecology of this species is crucial for the establishment of laboratory colonies and further experimentation. A laboratory colony of Cx. molestus was established based on field collected specimens from the Sydney region. The species was strongly stenogamous (i.e. mates successfully in confined spaces) and across all generations, over 95% of females laid autogenous (i.e. without reliance on a blood meal) egg rafts. Females delayed their first blood meal until after their autogenous egg raft had been laid, despite the availability of a host. The species readily fed on rodents and post-blood feeding egg rafts were significantly larger than autogenous egg rafts. Larval development rates were reliant on temperature rate and larval diet but adults emerging from larvae raised at a mean daily temperature of 12.0oC maintained the ability to lay autogenous egg rafts. Culex molestus has perfectly adapted to urban environments and further investigation is required to determine the importance of this species, and their habitats, to mosquito-borne disease risks.