Aedes albopictus

Overview

Known commonly as the "Asian tiger mosquito", Aedes albopictus has spread rapidly throughout the globe from eastern Asia to Europe, North and South America, and Africa in the last 30 years. During that time it has become one of the most significant and best studied invasive insects. The Asian tiger mosquito often lays its eggs in used tires, which are then transported around the globe to be recycled or retreaded. Ae. albopictus also lays its eggs in other natural and artificial water containers. Like most mosquitoes, Ae. albopictus requires a blood meal to complete its life cycle and blood feeds on many different animals, but has been shown to prefer humans. Its tendency to lay eggs in tires and other human refuse, along with its preference to feed on humans, results in close association with some human populations. The spread of the Asian tiger mosquito has raised public health concerns, as it is a vector for diseases such as chikungunya virus, dengue virus, dirofilariasis, and others.

Identification

Ae. albopictus is a smaller mosquito with black and silver scales. It can be confused with other native Aedes mosquitoes such as Ae. aegypti and Ae. japonicus. Its most distinctive feature is the bold white stripe down the center of its scutum (the dorsal surface of the thorax).

Life Cycle

Ae. albopictus lays its eggs on the sides of water holding containers, just above the waterline. When rainfall causes the water level to rise, the eggs hatch into larvae. The larvae develop through 4 larval instars which use a siphon tube to breathe and feed on organic matter in the water. The larvae then enter the short-lived pupal stage, which can move but cannot feed. Shortly thereafter the adult mosquito emerges. An adult female must take a blood meal in order to develop eggs.

Research: A Vector For Disease

Much of the research surrounding surrounding Ae. albopictus is focused on its status as a disease vector. A review of the literature regarding the vector status of Ae. albopictus found very little evidence for its importance as an urban vector for dengue virus. Instead, Ae albopictus appears the most important in certain areas where dengue is present, but its most important vector (Aedes aegypti) is absent (Gratz 2004). Likewise, a study by the Centers for Disease Control and Prevention found that there is no evidence Ae. albopictus is currently a vector of human disease in the United States (Moore and Mitchell 1997). However, Ae. albopictus has been shown in the lab to be a competent vector of human diseases such as chikungunya, eastern equine encephalitis, West Nile virus, and dengue. In addition, dengue and other viruses have been isolated from wild specimens outside the United States (Moore and Mitchell 1997). Unlike the closely related Ae. aegypti which has a strong association with humans, Ae. albopictus is an opportunistic feeder that readily feeds on both humans and other animals. While this property may make it a less efficient vector for diseases that spread from human to human, it may act as a "bridge vector" for new viruses to spread from animals to humans (Paupy et al. 2009). As such, Ae. albopictus is second only to Ae aegypti in importance as a vector of dengue (Benedict et al. 2007), is beginning to be implicated as an important vector of chikungunya (Paupy et al. 2009), and may yet be an important vector of other diseases in the future.

Research: An Invasive Species

Aedes albopictus is an extremely invasive species and has been called the most invasive mosquito. Its spread has also been relatively recent and over a short period of time (approximately 30 years). For these reasons it has been extensively studied as an invasive species. Benedict et al. (2007) used occurrence data of Ae. albopictus along with environmental data to determine areas of likely habitat for the invasive mosquito. Using this information, combined with other factors like the import of used tires, they created a global risk map for the continued spread of the Asian tiger mosquito. Below is the risk map they created for the lower 48 United States. Yellow regions are areas where Aedes albopictus has been collected, and the red areas are where their model predicts it might be able to spread and survive. The development of models such as this one could help predict risk for the spread of other invasive insect disease vectors.