Taxonomic name: Aedes albopictus (Skuse, 1895)
Synonyms: Culex albopictus Skuse, 1895, Culex albopictus Skuse,1895
Common names: Asian tiger mosquito (English), forest day mosquito (English), mosquito tigre (Spanish), moustique tigre (French), tiger mosquito (English), tigermücke (German), zanzare tigre (Italian)
Organism type: insect
The Asian tiger mosquito is spread via the international tire trade (due to the rainwater retained in the tires when stored outside). In order to control its spread such trading routes must be highlighted for the introduction of sterilisation or quarantine measures. The tiger mosquito is associated with the transmission of many human diseases, including the viruses: Dengue, West Nile and Japanese Encephalitis.
Adults are known as tiger mosquitoes due to their conspicuous patterns of very black bodies with white stripes. Also, there is a distinctive single white band (stripe) down the length of the back. The body length is about 3/16-inch long. Like all mosquitoes, Asian tiger mosquitoes are small, fragile insects with slender bodies, one pair of narrow wings, and three pairs of long, slender legs. They have an elongate proboscis with which the female bites and feeds on blood.
agricultural areas, coastland, estuarine habitats, lakes, marine habitats, natural forests, planted forests, range/grasslands, ruderal/disturbed, scrub/shrublands, urban areas, water courses, wetlands
Aedes albopictus is a treehole mosquito, and so its breeding places in nature are small, restricted, shaded bodies of water surrounded by vegetation. It inhabits densely vegetated rural areas. However, its ecological flexibility allows it to colonize many types of man-made sites and urban regions. It may reproduce in cemetery flower pots, bird baths, soda cans and abandoned containers and water recipients. Tires are particularly useful for mosquito reproduction as they are often stored outdoors and effectively collect and retain rain water for a long time. The addition of decaying leaves from the neighboring trees produces chemical conditions similar to tree holes, which provides an excellent substrate for breeding. Ae. albopictus can also establish and survive throughout non-urbanized areas lacking any artificial containers, raising additional public health concerns for rural areas (Moore 1999, in Eritja et al. 2005).
The tiger mosquito is an aggressive outdoor day biter that has a very broad host range and attacks humans, livestock, amphibians, reptiles and birds (Eritja et al. 2005). In one survey of biting rates a level of 30 to 48 bites per hour was recorded (Cancrini et al. 2003).
Mosquitoes are vectors of many relevant human diseases from Malaria to filariasis (caused by Dirofilaria immitis (Naya and Knight 1999, in Eritja et al. 2005)). Ae. albopictus may be a matter of particular concern as a bridge vector for the West Nile virus because it inhabits rural areas and has a wide host range including birds, so that it can readily pass enzootic cycles to humans.
There are a total of four Flaviviruses, ten Bunyaviruses and seven Alphaviruses that Ae. albopictus is known to be receptive to in laboratory conditions. These include Yellow Fever, Rift Valley Fever, Chikungunya and Sindbis (all of which are present in the Mediterranean). Of these Ae. albopictus is known to be receptive in field conditions to three Flaviviruses (Dengue, West Nile and Japanese Encephalitis), six Bunyaviruses (Jamestown Canyon, Keystone, LaCrosse, Potosi, Cache Valley and Tensaw) and one Alphavirus (EEE). Other circulating viruses in the Mediterranean that are pathogenic to humans (but which the receptivity of Ae. albopictus has not been observed or tested in the laboratory) include Israel Turkey virus, Tahyna and Batai. However the extent to which Ae. albopictus can transmit diseases in the real world is unclear and depends on many factors including numbers, whether it bites humans, whether it takes blood meals from multiple people and how effectively the virus makes it from the mosquito’s gut to its salivary glands. Currently there is solid evidence for the tiger mosquito’s role in the transmission of only two diseases: Dengue and Chikungunya (Enserink, 2008). However, the recent outbreak Chikungunya virus in the Indian Ocean vectored by Ae. albopictus has been shown to be caused by a single nucleotide mutation in the virus that allowed it to more effectively use the tiger mosquito as a vector. Similar scenarios could happen with Dengue and other viruses that the mosquito was shown to transmit in the lab (Enserink, 2008).
Ae. albopictus has been demonstrated to have a competitive advantage over a number of other mosquito species including Ae. Aegypti (O’Meara et al. 1995; Juliano, 1998; Lounibos, 2002; Braks et al. 2004 in Vezzani and Carbajo, 2008). Ae. aegypti is an even more important vector of diseases than Ae. albopictus. This is largely because Ae. albopictus has such as wide host range compared to Ae. aegypti which feeds almost exclusively on humans (Enserink, 2008). Because diseases like Dengue affect only primates, if Ae. albopictus feeds on a lizard or bird after a human, the disease is not transmitted. Thus the actual consequence of the potential displacement of Ae. aegypti by Ae. albopictus in terms of diseases transmission remains unknown in many regions. Professor Gubler predicts that the spread of Ae. albopictus will actually result in a net gain for public health because in many places, it is displacing Ae. aegypti populations (Enserink, 2008). Indeed there are many studies that report Ae. albopictus outcompeting mosquito larvae of other species such as Ochlerotatus triseriatus, a vector for La Crosse Virus (Bevins, 2008) and Ae. japonicas (Armistead et al. 2008). However Didier Fontenille of the Institute of Research for Development in Montpellier, France disagrees with Gubler citing outbreaks of Chikungunya in the Indian Ocean Islands, La Reunion island and Italy as evidence of the tiger mosquito’s potential devastating impacts (Enserink, 2008).
Native range: Ae. albopictus occurs thoughout the Oriental Region from the tropics of Southeast Asia, the Pacific and Indian Ocean Islands, north through China and Japan and west to Madagascar.
Known introduced range: Ae. albopictus has been one of the fastest spreading animal
species over the past two decades (Benedict et al. 2007). The mosquito has been introduced in North and South America, with more recent introductions having occurred in Africa, Australia and Europe, where it is established in Albania and Italy and where it has been detected in France (Eritja et al. 2005). In the United States, it is established in most states east of the Mississippi River as far as Minnesota and Delaware (Source: Novak). It has spread to at least 28 countries outside its native range around the globe (Benedict et al. 2008). Climate change will likely allow tiger mosquitoes to further increase their range by increasing areas of suitable climate. These areas could include Australia (Dr. Moira McKinnon pers. comm. in Beilharz 2009), New Zealand (Derraik, 2004) and further north in the United States (Phillips, 2008).
Introduction pathways to new locations
Horticulture: During the summer of 2001, containerised shipments from China of the plant known as Lucky Bamboo (Dracaena spp.) were found to contain A. albopictus on inspection by quarantine officers on arrival at Los Angeles, USA (Linthicum 2001, in Eritja et al. 2005). This route of spread became an issue only after traders swapped from dry freight to low cost shipping routes (which required the plants to be shipped in standing water to preserve them for the longer voyage).
Nursery trade: The trade in "lucky bamboo" (Dracaena spp.) is increasing because it has cultural relevance within the Asiatic communities in the US and elsewhere, and it has also gained worldwide attention as a popular gift. Destination wholesale nurseries containing lucky bamboo in California were found to be infested by the tiger mosquito (Madon et al. 2002, in Eritja et al. 2005). Similarly large nurseries in the Guangdong province of China, where the climate is suitable for A. albopictus, should be kept under observation (Madon et al. 2002, in Eritja et al. 2005).
Road vehicles (long distance): The adult flight range is quite short. Therefore, most medium and long range colonization is the result of passive transportation by humans. This may occur, for example, in the movement of used tires in trucks (Eritja et al. 2005).
Ship: During the summer of 2001, containerised shipments from China of lucky bamboo (Dracaena spp.) were found to contain Aedes albopictus on inspection by quarantine officers on arrival at Los Angeles, USA (Linthicum 2001, in Eritja et al. 2005). This route of spread only became an issue after traders changed from dry freight to low cost shipping routes (which required the plants to be shipped in standing water to preserve them for the longer voyage).
Transportation of habitat material: Movement of moist vegetation, wet tires or water containers that hold eggs or larvae.
Transportation of habitat material: Movement of moist vegetation, wet tyres or water containers that can hold eggs or larvae.
Local dispersal methods
Garden escape/garden waste:
Natural dispersal (local): The adult flight range is quite short, as expected for a scrub-habitat mosquito. The spreading of A. albopictus is quite slow; it has not spread along the Mediterranean coast from Italy to France, in spite of relatively short distances (Eritja et al. 2005).
Road vehicles: May be spread in trucks transporting used tyres.
Transportation of habitat material (local): Movement of moist vegetation, wet tyres or water containers that can hold eggs or larvae (Eritja et al. 2005).
Preventative measures: Starting in 1992, several countries in South America (Venezuela, Chile, Bermuda, Costa Rica, Argentina and Brazil) have dictated embargoes on used tire importations, in an attempt to prevent mosquito and dengue introduction into areas where a potential vector, A. aegypti, is already present (Eritja et al. 2005).
Source reduction strategies (such as larval or adult control within tire dumps) have proven to be difficult and relatively inefficient due to the shape and abundance of the water surfaces (Eritja et al. 2005).
Quarantine and inspection measures in Australia have allowed detection of larval introductions of the tiger mosquito (Eritja et al. 2005). As immediate control measures have been applied, Ae. albopictus has not as of yet become established on the continent (R. Russell, pers. comm., in Eritja et al. 2005).
In the Netherlands horticultural companies have taken steps to reduce the risk, for instance, by treating shipments before they leave China (Enserink, 2008).
Predicting the potential spread of the tiger mosquito may be important in alerting the appropriate authorities to take preventative action. Areas at risk in Europe would have mean winter temperatures higher than 0°, at least 500mm rainfall per year and a warm month mean temperature of 20°. It is believed that less than 300mm rainfall per year would make establishment extremely unlikely. (Eritja et al. 2005).
Physical Control: Ae. albopictus is not readily captured by most traps, even those that catch other mosquito species. However, recently there are new traps being developed: BG-SentinelTM and the Collapsible Mosquito Trap (CMT-20TM). These traps use ammonia, fatty acids and lactic acids to produce a smell similar to that of a human body in an upward air current. The addition of carbon dioxide greatly improves the number of mosquitoes captured. When carbon dioxide is added these traps collect about 33 times more than standard light traps (Meeraus et al. 2008).
Biological Control: Bioengineering is a major focus of research in agricultural and public health entomology. Oxford Insect Technologies (http://www.oxitec.com/) have created a strain of Ae. aegypti with a dominant tetracycline-repressible gene. The aim is to release transgenic males in the field; the progeny of matings with wild females will die. Ultimately we will select a sex-linked strain that will kill only female progeny, providing a “driver” for the lethal gene in the field. Current research is studying the ‘fitness’ of such transgenic strains and will also attempt to engineer strains of Ae. albopictus (Insects and Infectious Diseases, 2006).
Another form of biological control that is currently being investigated is use of an entomopathogenic fungus Metarhizium anisoplia. Results from laboratory studies showed that longevity of M. anisopliae-infected Ae. aegypti and Ae. albopictus is significantly lower than that of uninfected mosquitoes. The challenge is to find and apply an effective methodology that will result in reduced vectorial capacity of mosquitoes in the field (Scholte et al. 2008).
Integrated Management: In Switzerland, monitoring systems consisted of over 300 strategically positioned oviposition traps along main traffic axes, including parking lots within industrial complexes, border crossings and shopping centres.. Bi-weekly control visits to all traps were conducted between April and November 2007. As soon as eggs were detected, the surrounding vegetation within a perimeter of about 100 metres was sprayed with permethrin against adult mosquitoes. Stagnant water was treated with Bacillus thuringiensis and in some cases with diflubenzuron to control the larval stages (Wymann et al. 2008).
Obtains energy by feeding on plant nectar. Females require blood to produce eggs. Although primarily a mammalian feeder, will accept blood from a wide variety of hosts.
The females lay desiccation-resistant eggs above the surface of the water in treeholes, tires or other water-holding containers. Their ability to breed in artificial containers facilitated their passive spread in the last decades through main transportation routes (Lounibos 2002 in Vezzani and Carbajo, 2008)They rely on rainfall to raise the water level and inundate the eggs for hatching. 150 to 250 eggs are laid per ovipostion. There are 1 to 4 ovipositions per female (ISSG 2004). The active reproductive period occurs in Japan and southwestern US from late Spring to early fall (Alto and Juliano 2001, in Eritja et al. 2005). In Rome, larvae are found from March to November, but some females are active until December (Di Luca et al. 2001, in Eritja et al. 2005). The eggs from strains colonizing temperate regions resist lower temperatures than those from tropical areas (Hanson and Craig 1995, in Eritja et al. 2005). Additionally, in these strains, the combination of short photoperiods and low temperatures can induce the females to lay diapausing eggs which can hibernate (Hanson and Craig 1995, in Eritja et al. 2005). This feature of diapause, which most other tropical mosquitoes lack may be one of the keys to the success of Ae. albopictus (Enserink, 2008). Overwintering is necessary north of the +10°C January isotherm (Mitchell 1995, Knudsen et al. 1996, in Eritja et al. 2005).
The mosquito has four distinct life stages, which consist of egg, larva, pupa and adult. The first three stages occur in water. The adult is the freeflying insect that feeds on humans, other animals and the juice of plants (Lutz 2002).
This species has been nominated as among 100 of the "World's Worst" invaders
Reviewed by: Dr. Roger Eritja Spain
Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG)
Updates on management information with support from the Overseas Territories Environmental Programme (OTEP) project XOT603, a joint project with the Cayman Islands Government - Department of Environment
Last Modified: Tuesday, 27 October 2009