As Australian homeowners act on incentives to install rainwater tanks in response to global warming, they are creating new breeding opportunities for the Aedes aegypti mosquito, which carries dengue fever and prefers to lay its eggs in stagnant water.

According to a new study, proliferation of domestic water storage systems is likely to provide a greater stimulus to the southward expansion of dengue than a warming climate (Funct. Ecol., doi:10.1111/j.1365-2435.2008.01538.x; 2009)

Egg-static bugs: Mosquitoes breed in standing water Credit: Nature's Images/Photo Researchers, Inc.

“The potential direct impact of climate on the distribution and abundance of Aedes aegypti is minor when compared to the potential effect of changed water storage behavior,” says Michael Kearney, a researcher at the University of Melbourne and lead author of the modeling study.

Federal and state governments offer cash rebates to householders to install water collection and recycling systems as the southern half of the continent endures the kind of extended drought predicted to be more frequent as a result of global warming trends.

Dengue was prevalent as far south as Sydney in the late 1800s but has been restricted to the tropical north since the 1960s, when reticulated water supplies largely replaced domestic storage systems.

Some experts have called the dengue fever problem in Australia the worst the country has seen in 50 years. In the past several months, more than 400 cases of dengue fever were reported in north Queensland, where heavy monsoon rains caused prolonged and widespread floods.