June 4, 2009

Midges keep invasive mosquitoes in check

U.S. medical entomologists have discovered tiny flies known as midges can be used to control invasive Asian tiger mosquitoes that can carry dengue fever.

University of Illinois scientists led by Barry Alto said the larvae of midges (Corethrella appendiculata) eat more of the larvae of the invasive mosquito than of the native Eastern treehole mosquito (Aedes triseriatus). That, the scientists said, allows the native mosquitoes to survive even though the invasive mosquitoes are better at consuming resources.

The researchers found inherent size differences between the mosquito species -- the treehole mosquito is larger than the Asian tiger mosquito, which makes it less vulnerable to predation from the small, but voracious, predatory midge.

Size is having a major effect in terms of how the prey are getting consumed, said Alto. This is another mechanism that allows the native mosquito to hang on and co-exist with the invasive mosquitoes in certain areas where predators are present.

The study that included UI researchers Banugopan Kesavaraju and Steven Juliano, along with Philip Lounibos of the University of Florida, appears in the British Ecological Society's Journal of Animal Ecology.