New Model Sheds Light on Mosquito Spread in a Changing Climate

A new study, published online in the British Ecological Society journal, Functional Ecology, uses an innovative model to predict the spread of human disease vectors in a changing climate. Warren Porter, at the University of Wisconsin-Madison, has developed a unique model, 'NicheMapper', which allows researchers to answer the question: "Where would a species with a particular set of properties best survive and function on the planet?" Uniquely, the model also allows an organisms potential for evolutionary change to be incorporated, allowing the researchers to examine a range of scenarios.

The study focused on the dengue fever vector, the mosquito Aedes aegypti, and on its distribution and abundance in Australia. At present, the mosquito is confined to areas around Queensland, however, by modelling the insect's life history traits, capacity to evolve and climate change scenarios, the researchers conclude that a warming climate will allow the mosquito to expand its range into several populated areas of the continent, over the next 40-years. These conclusions are also likely to apply to populations of the mosquito found elsewhere in the world.

The researchers found that onefactor limiting the ability of the mosquito to spread would be the availability of standing water in which to lay its eggs. Simple measures, such as covering pools and water tanks, could have a large effect in reducing the spread of the insect. However, NicheMapper also allowed the researchers to model the effects on the species' distribution if the mosquito evolved to develop eggs tolerant of dessication; observed in other closely related species. In this case, combined with climate change, the mosquito could spread far, and rapidly.

Warren Porter claims that NicheMapper can be used to model the spread of almost any species on the planet; for example mapping the likely pattern of spread of invasive species. He has developed a company, 'Animaps' to make the software available to the scientific and policy communities.