How Is the Tiger Mosquito Successful in Its New Environment?

A highly adaptable and resourceful species, the Asian tiger mosquito (Aedes albopictus), has been spreading throughout much of the United States since its accidental introduction into the United States in 1985. Its disease-carrying potential has made it a significant public health concern, but public agencies are finding the insect exceptionally challenging to control. A map of the affected states and a picture of the insect is in Reference 3.

Habitat and Characteristics

• The tiger mosquito is native to warm, humid regions of Asia, where holes in trees are its preferred breeding and larval development habitat. It is a medium-sized, fast-moving, moderately aggressive insect. It derives its common name from its distinctive black-and-white-striped markings. Unlike most other species of mosquitoes, it feeds during the daylight hours. A carrier or "vector" for many diseases, the tiger mosquito is known to transmit dog heartworm disease. It may have the potential to transmit diseases to humans, such as yellow fever, West Nile virus, St. Louis encephalitis and LaCrosse encephalitis.

World Traveler

• Because they contain a high percentage of rubber, many U.S. companies import used tires from Asia for industrial use. It is believed that the Asian tiger mosquito first entered the United States on a freight vessel carrying such a cargo from Japan to Houston, Texas. The dark water-filled cavities of tires are rich with organic material, providing the tiger mosquito with the perfect mobile habitat. Surveillance of the insect reveals that it

  took advantage of this mode of travel on many subsequent occasions.

Adaptability

• Avoiding dry climates, the pest spread northward and eastward from the Gulf Coast of Texas. It next appeared in Baltimore, Maryland at a used tire processing plant in 1987.

  Maryland public health officials have observed the mosquito is not fussy as to living arrangements. It requires a water-filled container. There is a marked preference to live outdoors, rather than indoors, and in the shade, rather than in direct sunlight.

Population Dynamic Theory

• Barry Alto, a University of Florida doctoral candidate in entomology, explains that "according to population dynamic theory, organisms are better able to get a foothold in new sites when they grow really quickly right in the beginning." Research conducted by Alto and University of Illinois biology professor Steve Juliano demonstrates that the tiger mosquito got its initial breeding boost thanks to the warming United States climate. They found that a temperature increase of just a few degrees facilitates significant tiger mosquito population increases.

Pest Control Program Challenges

• The adult insect and its larvae are susceptible to various toxic spores, growth-inhibiting agents, insecticides and predators, such as mosquitofish and cannibal mosquitoes. The problem is that the agencies charged with controlling the pest lack the legal authority and resources to seek out and address the pest in its isolated and widespread breeding habitat. The most effective method of control is for individual property owners to eliminate or otherwise address potential containers, including everything from old aluminum cans to decorative ponds, that could provide the insect with the necessary breeding environment.