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Spring 2010

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

June 1, 2010

Black and white and mean all over

The yearly onslaught of Asian tiger mosquitoes has begun, and these pests will torment gardeners, picnickers and porch-sitters until the next hard freeze.

Unlike native mosquitoes, which feed at dawn and dusk, invasive tiger mosquitoes bite at all hours, often employing the stealth tactic of feeding behind our knees and elbows. They bite quickly. Swat at them and they seem to vanish.

About five days after filling her tank with your blood, a female will lay eggs on a hard surface just above a source of water. When rain raises the water level, the larvae hatch and begin to feed on decaying plant matter in the water. In a week or so, those "wigglers" will have transformed and taken flight as blood-hungry females and nectar-sipping males.

People can reduce their neighborhood's swarm by eliminating standing water in gutters, buckets and overflow dishes beneath potted plants. Frequent replacement of birdbath water is critical.

Tiger mosquitoes are potential vectors for dengue fever, viral encephalitis, dog heartworm, West Nile virus and chikungunya fever.

Water gardeners are wise to stock their backyard ponds with Eastern mosquitofish, native minnows with a voracious appetite for mosquito larvae. The small fish have difficulty surviving the winter in pools shallower than three feet, but they can be kept alive through the cold months in a sunny indoor tank filled with pond water and a fistful of aquatic plants.

SOURCES: Centers for Disease Control and Prevention; University of Florida Institute of Food and Agricultural Sciences; D.C. Fisheries and WIldlife Division

Asian tiger mosquitoEastern mosquitofish, Gambusia holbrooki