Does male diet influence mosquito reproduction?

My latest publication has appeared in the Journal of the American Mosquito Control Association in December 2012. This paper reports on some biological experiments conducted by my PhD student Nur Abu Kassim. She was interested in investigating the role of diet (including how much food immature stages ate and if adult mosquitoes had access to sugar) on male mosquitoes and the resulting egg development by females.

Nur conducted her experiments using Culex molestus, this species is a member of the Culex pipiens group. This group of mosquitoes is important internationally as it contains species closely associated with the transmission of disease-causing pathogens, in particular West Nile virus. Culex molestus is an interesting species in that it can develop its first batch of eggs without a blood meal. You can read about our earlier studies here and here.

The results indicated that diet of male mosquitoes, both access to food in immature stages and access to sugar as adults, influenced the number of autogenous eggs and hatching rates of those eggs.

Here is the abstract:

Culex molestus is an obligatory autogenous mosquito that is closely associated with subterranean habitats in urban areas. The objective of our study was to investigate the influence of larval and adult nutrition on the role of males in determining the expression of autogeny in Cx. molestus. Mosquitoes raised at low and high larval diets had sex ratio, wing length, mating rates, autogenous egg raft size, and hatching rates recorded. There was a higher ratio of males to females when raised at a low larval diet. Mean wing lengths of both males and females were significantly greater when raised at the high larval diet regime. Regardless of larval or adult diet, males mated with only a single female. Mosquitoes raised at the higher larval diet regimes developed significantly more autogenous eggs. However, the egg raft size was reduced when adult females were denied access to sugar. The results of this study indicate that the performance of males in the reproductive process is influenced by both larval diet and adult sugar feeding.

Full reference:

Kassim NFA, Webb CE & Russell RC. 2012. The Importance of Males: Larval Diet and Adult Sugar Feeding Influences Reproduction in Culex molestus. Journal of the American Mosquito Control Association 28(4):312-316. online

 

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Urban development and mosquito-borne disease

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In November 2012, I presented some of my work associated with Mosquito Risk Assessment and urban planning at the Australian Entomological Society and Australasian Arachnological Society – 2012 Conference, Hobart, Tasmania.

The title of my presentation was “Taking an ecological approach to wetland rehabilitation and urban development to reduce the risks of mosquito-borne disease in Australia“. The abstract is below.

Mosquito-borne disease management in coastal Australia faces many challenges. Increasing urbanisation is bringing the community closer to productive mosquito habitats but environmental management of coastal wetlands is often in conflict with effective mosquito control strategies. Annually abundant pest and vector mosquito populations bring with them the risks of disease caused by Ross River virus and Barmah Forest virus. Large scale wetland rehabilitation projects are increasing the availability of productive mosquito habitat while also providing refuge for known reservoir hosts (e.g. macropods, birds) of mosquito-borne viruses. Balancing the desire for environmental conservation with the need to protect the health of human communities requires integrated urban design strategies combined with targeted research. While broadscale mosquito control activities are restricted due to unresolved issues associated with potential ecological impacts, local authorities are looking to use planning instruments to minimize the impacts of local mosquitoes by requiring mosquito risk assessments to be conducted by developers, placing stringent controls on constructed water bodies and the incorporation of buffer zones between residential allotments and mosquito habitats. However, the effectiveness of these strategies is often site-specific and is determined by the local mosquito fauna. Potentially important onsite mosquito habitats are also being created through Water Sensitive Urban Design strategies intended to increase water conservation through above- and below-ground water treatment and storage.

Some background to the presentation is presented here.

Following this presentation, an article of mine was published on The Conversation website. “Using urban planning to reduce mosquito-borne disease” discusses many of the issues surrounding urban development and the increasing risk of mosquito-borne disease in Australia.