There is very little communication that occurs between individuals of this species. Almost all communication is involved with mating. Antennae contain auditory receptors that allow the males to hear the whine of females which helps to locate them. Once in the same vicinity, males engage in lekking behavior, forming clusters in mid-air which invite females to mate. The males then secrete a substance that helps to officially begin the mating process. Individuals pair off, mate, and don't interact again.
Besides the auditory receptors, all mosquitoes in the species have compound eyes to help locate just about anything they need (mates, food, areas to lay eggs).
Communication Channels: acoustic ; chemical
Perception Channels: visual ; acoustic
Aedes albopictus is a notorious vector of various harmful pathogens to a number of species. All focus placed on the species concerns controlling it rather than conserving it.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Eggs of Aedes albopictus are laid along the side of artificial or man-made containers and will hatch when water levels rise above the location of the egg, submerging it. The eggs will hatch in water with low turbidity and a pH ranging from 5.2 to 7.6 (optimal range from 6.8 to 7.6). The ideal pool of water has a high organic nitrogen content for feeding upon. Larval size and duration of larval development are influenced by a variety of factors: temperature, food supply, crowding, and sex. Larval development includes four instars and can be as short as four days, or as long as 42 in a situation where the larva lacks adequate food, in which case it will die.
Larvae will eventually close themselves in pupaes, a process which under ideal conditions will last two days. This number can vary for males and females, though. The average number of hours for males is 32 to 36, while for females it is between 49 and 52. At this point an adult will emerge from the pupa, where it will soon look to mate. The adults have reached sexual maturity once they have left the pupa, and begin feeding and mating within two or three days.
Development - Life Cycle: metamorphosis
Aedes albopictus acts as a parasite and a vector to a large variety of other species. Mosquitoes have a wide range of species they can feed upon. After being bitten by a mosquito, a host will become irritated in that spot due to a typical immune response against mosquito saliva. When feeding on a host, the species can pass on one of many different arboviruses, along with protzoans and filarial nematodes. Aedes albopictus is a known vector of dengue fever, yellow fever, West Nile virus, Eastern equine encephalitis, and Venezuelan equine encephalitis among many more. Mosquitoes are known to have caused outbreaks of Chikungunya Fever in both France and Italy. It is also notorious for vectoring parasitic roundworms Dirofilaria immitis, which cause heartworm in domestic dogs and cats. Because of the large number of pathogens Aedes albopictus carries and its ability to inhabit much of the world throughout the year, mosquitoes spread significant amounts of disease.
Negative Impacts: injures humans (bites or stings, carries human disease); causes or carries domestic animal disease
Asian tiger mosquitoes provide no benefits to humans.
A wide range of organisms prey Aedes albopictus as larvae when they are most defenseless. Various families of fungi infect larvae and tests have been done to see if they could be considered as a biological control agent of mosquitoes. Specifically, Coelomonoyces stegomyia and Tolypocladium cylindrosporum fungi cause damage to larval populations. Protozoan parasites can also cause damage, specifically to the midgut of larvae. Ascogregarina taiwanensis is one protozoan example, as well as other members from the genus Ascogregarina. Nematodes have been found parasitizing Asian tiger mosquitoes, but only in laboratory tests. Romanomermis culicivorax which has a history of burrowing into the cuticle of larval mosquitoes was introduced in experiments, but has not been found in nature parasitizing on Aedes albopictus. Other pathogens in bacterium and ciliate families have also been found to cause damage.
Aedes albopictus plays a large role in the spread of disease, as females have the potential to spread blood-borne diseases. This is of particular concern with zoonotic diseases as mosquitoes feed on many species of mammals and birds as well as humans.
Ecosystem Impact: parasite
Species Used as Host:
Commensal/Parasitic Species:
Males of the species are not parasitic. They feed on nectars and sugar-rich plant juices. The females also feed on these juices, but need a blood meal to develop eggs. Asian tiger mosquitoes are efficient in that they can feed on many different species (of both mammals and birds). Aedes albopictus is an opportunistic feeder but prefers mammals above all else. Some of the most common species fed upon are domestic dogs, deer, rabbits and humans. They can feed on squirrels, opossums, bovines, raccoons, turtles, rats, and cats. This host variability allows this species to thrive in a wide range of environments.
When searching for a host, there are two phases. First, a female mosquito exhibits a nonspecific searching behavior until the perception of host stimulants. A mosquito then targets the host and begins an approach. Lastly, this mosquito lands on its host and thrusts its proboscis through the skin to find a vessel to feed from (making females of this species solenophagic).
Animal Foods: blood
Plant Foods: nectar
Primary Diet: herbivore (Nectarivore )
As explained by their colloquial name, Asian tiger mosquitos (Aedes albopictus) are native to Eastern Asia, stretching into India, Japan, and several islands in the Pacific (Australasia). Due to A. albopictus excellent ability to colonize new environments, it has been introduced to a variety of other places in the world. Over the past thirty years the species has spread to Italy and other regions in the Mediterranean basin, as well as parts of Africa, Madagascar, Brazil, Central America, the Caribbean, and most of the United States (specifically the East coast and the Midwest).
Biogeographic Regions: nearctic (Introduced ); palearctic (Native ); oriental (Native ); ethiopian (Introduced ); neotropical (Introduced ); oceanic islands (Introduced )
Aedes albopictus chooses a habitat based on availability of food resources and availability of locations for reproduction and development. The species is capable of utilizing natural as well as artificial container habitats. It is perhaps most well known for utilizing tires, but it has since adapted the ability to develop in a range of natural and artificial areas including bird baths, clogged gutters, and litter.
Because members of this species are weak fliers, they remain within the same habitat their entire lives. Besides having a proper breeding and reproduction habitat, proper food resources must be available as well. This mosquito has developed very weak host specificity, and thus does not have trouble finding food in most environments.
Habitat Regions: tropical ; terrestrial ; freshwater
Almost all studies on lifespan of Aedes albopictus have focused on the life of the female, so not much is known about the longevity of the male. It seems that environmental factors have a large effect on how long an individual can live. In a temperate climate with relatively high humidity, the average lifespan was between 30 and 40 days. In the laboratory, various experiments with different foods in different amounts could allow females to live up to 117 days. This was an extreme situation which is not possible in the natural environment.
Range lifespan
Status: captivity: 117 (high) days.
Typical lifespan
Status: wild: 30 to 40 days.
Aedes albopictus received its common name because of its distinguishable pattern of white and black stripes along it's palpus and tarsi. Beyond that, they are similar to most others in the Culicidae family (except for their pointed abdomens). Males are slightly smaller than females in the species, but they are very similar morphologically. The exception to this lies in the antennae (resting at the top of the mosquito, just above the mouthparts) which are much bushier in the males, and the maxillary palps which are longer in males than their proboscis (which isn’t needed for sucking). In females the palps are much smaller than their proboscis, which is crucial for taking blood meals. Aedes albopictus has a black proboscis, eyes, and labium all at the anterior end of the insect, while the black scutum contains a white line dissecting the dorsal part of the mosquito in half. Tergites behind the scutum are dark with bright white markings on them. Most legs are alternating in color, but some are solely black.
Eggs of Aedes albopictus are shaped much like cigars. They are blunt at the anterior end and taper at the posterior end. Each egg is spotted with large, smoothly rounded outer tubercles, with small cell fields scattered around the rest of the egg. The eggs eventually hatch into larva, which are sometimes called wigglers, which are very small and must be studied under a microscope. They are active feeders, and thus are equipped with mouth parts. They also have long, protruding breathing siphons used for oxygen acquisition. Larva are lighter in color when compared to most other mosquito species. They are very similar to Aedes aegypti, which is a closely related species. There are a few small differences that help to distinguish the two species, located on the mesothorax and metathorax. For example, Aedes albopictus has long pleural hair groups lacking a long spine that can be found on the other species. Pupae are also aquatic. They retain the breathing siphon, but appear as a dark ball at the other end.
Range length: 2 to 10 mm.
Average length: 4 mm.
Average wingspan: 2.7 mm.
Sexual Dimorphism: female larger; ornamentation
Other Physical Features: ectothermic ; bilateral symmetry
Many different species from different phylum prey upon Aedes albopictus. The majority of these predators consume mosquitoes in their larval phase. For example, a copepod predator, Mesocyclops leuckarti pilosa has been found to have the ability to take out an entire group of larva in a container. Another copepod, Macrocyclops albidus, which has a wide geographic range (unlike Mesocyclops leuckarti pilosa) is able to knock out a dense population in tire piles in 8 to 10 weeks. Some flatworms in the phylum Platyhelminthes also prey on larvae. Other mosquitoes including various species in the Toxorynchites genus, have shown an excellent ability to maintain Asian tiger mosquito populations and are being considered as a possible control species.
Bats and birds are the most common predators of adult mosquitoes. In certain areas, spiders are known to catch Aedes albopictus and feed on them.
Known Predators:
Females can mate up to four times in a lifetime, depending on length of lifespan. Males typically have slightly shorter lifespans, but have fewer restrictions on mating. They can both mate multiple times with multiple individuals. Males will form leks, or swarms, a few feet off the ground, which will attract females. Males will secrete stimulants which provide one stimulus for ovarian development (blood meal provides the other stimulus). Mating will occur in flight and last for 5 to 15 seconds. At the end of the female’s gonotrophic cycle she oviposits her eggs, placing them at a few various locations.
Mating System: polygynandrous (promiscuous)
Once females emerge from pupae, they take in a blood meal within the first two the three days, which is vital for the development of eggs. There is no one mating season for Aedes albopictus, but the species is likely to mate during the rainy season which varies geographically. This assures the quickest development time for the eggs, which begin hatching once submerged in a stagnant pool of water. Females may lay from 45 to 200 eggs per year.
Breeding interval: Each gonotrophic cycle lasts about four days.
Breeding season: Breeding occurs during the rainy season, which varies geographically.
Range eggs per season: 45 to 200.
Average time to independence: 8 days.
Average age at sexual or reproductive maturity (female): 8 days.
Average age at sexual or reproductive maturity (male): 7 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
There is no parental investment once the female has laid her eggs in a suitable location.
Parental Investment: no parental involvement
Aedes albopictus (Stegomyia albopicta), from the mosquito (Culicidae) family, also known as the (Asian) tiger mosquito or forest mosquito, is a mosquito native to the tropical and subtropical areas of Southeast Asia. In the past few centuries, however, this species has spread to many countries through the transport of goods and international travel.[1] It is characterized by the white bands on its legs and body.
This mosquito has become a significant pest in many communities because it closely associates with humans (rather than living in wetlands), and typically flies and feeds in the daytime in addition to at dusk and dawn. The insect is called a tiger mosquito for its striped appearance, which resembles that of the tiger. Ae. albopictus is an epidemiologically important vector for the transmission of many viral pathogens, including the yellow fever virus, dengue fever, and Chikungunya fever,[2] as well as several filarial nematodes such as Dirofilaria immitis.[3] Aedes albopictus is capable of hosting the Zika virus[4][5] and is considered a potential vector for Zika transmission among humans.
In 1894, a British-Australian entomologist, Frederick A. Askew Skuse, was the first to scientifically describe the Asian tiger mosquito, which he named Culex albopictus (lat. culex "gnat", "midge" and albopictus "white-painted").[6][7] Later, the species was assigned to the genus Aedes (gr. άηδής, "unpleasant")[8] and referred to as Aedes albopictus.[9] Like the yellow fever mosquito, it belongs to the subgenus Stegomyia (Gr. στέγος, "covered, roofed", referring to the scales that completely cover the dorsal surface in this subgenus, and μυία, "fly") within the genus Aedes.[10] In 2004, scientists explored higher-level relationships and proposed a new classification within the genus Aedes and Stegomyia was elevated to the genus level, making Aedes albopictus now Stegomyia albopicta. This is, however, a controversial matter, and the use of Stegomyia albopicta versus Aedes albopictus is continually debated.[11][12][13]
The adult Asian tiger mosquito is less than 10 mm (0.39 in) long from end to end with a striking white and black pattern.[6][14][15] The variation of the body size in adult mosquitoes depends on the density of the larval population and food supply within the breeding water. Since these circumstances are seldom optimal, the average body size of adult mosquitoes is considerably smaller than 10 mm. For example, the average length of the abdomen was calculated to be 2.63 mm (0.104 in), the wings 2.7 mm (0.11 in), and the proboscis 1.88 mm (0.074 in).[16]
The males are roughly 20% smaller than the females, but they are morphologically very similar. However, as in all mosquito species, the antennae of the males in comparison to the females are noticeably bushier and contain auditory receptors to detect the characteristic whine, almost inaudible to humans, of the female. The maxillary palps of the males are also longer than their proboscis, whereas the females' maxillary palps are much shorter. (This is typical for the males of the Culicinae.) In addition, the tarsus of the hind legs of the males is more silvery; the males' tarsomere IV is roughly 75% silver, whereas the females' is only about 60% silver.
The other characteristics do not differentiate between sexes. A single silvery-white line of tight scales begins between the eyes and continues down the dorsal side of the thorax. This characteristic marking is the easiest and surest way to identify the Asian tiger mosquito.
The proboscis is dark colored, the upper surface of the end segment of the palps is covered in silvery scales, and the labium does not feature a light line on its underside. The compound eyes are distinctly separated from one another. The scute, the dorsal portion of an insect's thoracic segment, is black alongside the characteristic white midline. On the side of the thorax, the scutellum, and the abdomen are numerous spots covered in white-silvery scales.
Such white-silvery scales can also be found on the tarsus, particularly on the hind legs that are commonly suspended in the air. The bases of tarsomeres I through IV have a ring of white scales, creating the appearance of white and black rings. On the forelegs and middle legs, only the first three tarsomeres have the ring of white scales, whereas tarsomere V on the hind legs is completely white. The femur of each leg is also black with white scales on the end of the "knee". The femora of the middle legs do not feature a silver line on the base of the upper side, whereas, the femora on the hind legs have short white lines on base of the upper side. The tibiae are black on the base and have no white scales.
The terga on segments II through VI of the abdomen are dark and have an almost triangular silvery-white marking on the base that is not aligned with the silvery bands of scales on the ventral side of the abdomen. The triangular marking and the silvery band are only aligned on abdominal segment VII. The transparent wings have white spots on the base of the costae. With older mosquito specimens, the scales could be partially worn off, making these characteristics not stand out as much.[14][16]
As with other members of the mosquito family, the female is equipped with an elongated proboscis that she uses to collect blood to feed her eggs. The Asian tiger mosquito has a rapid bite and an agility that allows it to escape most attempts by people to swat it. By contrast, the male member of the species primarily feeds on nectar and does not bite.
The female lays her eggs near water, not directly into it as other mosquitoes do, but typically near a stagnant pool. However, any open container containing water will suffice for larvae development, even with less than an ounce (30mL) of water. It can also breed in running water, so stagnant pools of water are not its only breeding sites. It is more likely to lay eggs in water sources near flowers than in water sources without flowers. It has a short flight range (less than 200 m (220 yd)), so breeding sites are likely to be close to where this mosquito is found.[17][18]
Other mosquito species may be visually confused with the tiger mosquito. Comparison with approved pictures is the best way to determine the species with certainty.[19] Behavioral cues like almost-silent flight and difficulty in catching combined with knowledge of the range of local endemic mosquitoes may also aid this process.
Some mosquitoes in North America, such as Ochlerotatus canadensis, have a similar leg pattern. In North and South America, Ae. albopictus can be distinguished from Aedes taeniorhynchus since only Ae. albopictus has back markings.
In Europe, the mosquito Culiseta annulata, which is very common, but does not occur in high densities, can be mistaken for an Asian tiger mosquito because of its black-and-white-ringed legs. However, this species is missing the distinctive white line that runs from the middle of its head and down the thorax. It is also considerably larger than Ae. albopictus, is not black and white, but rather beige and grey striped, and has wings with noticeable veins and four dark, indistinct spots. The Tree Hole mosquito or Aedes geniculatus – a native to Europe and North Africa- has also been mistaken for Ae. albopictus. This is because the Tree Hole mosquito has very white scales on a very similar body.[20]
In the eastern Mediterranean area, Ae. albopictus species can be mistaken for Aedes cretinus, which also belongs to the subgenus Stegomyia and uses similar breeding waters. Aedes cretinus also has a white stripe on the scute, but it ends shortly before the abdomen, and also has two additional stripes to the left and right of the middle stripe. So far Aedes cretinus is only located in Cyprus, Greece, North Macedonia, Georgia and Turkey.[21]
In Asia, the Asian tiger mosquito can be mistaken for other members of the subgenus Stegomyia, particularly the yellow fever mosquito Aedes aegypti (the most prevalent species in the tropics and subtropics), because both species display a similar black and white pattern. It can be hard to distinguish Ae. albopictus from the closely related Aedes scutellaris (India, Indonesia, Papua New Guinea, and the Philippines), Aedes pseudoalbopictus (India, Indonesia, Malaysia, Myanmar, Nepal, Taiwan, Thailand, and Vietnam) and Aedes seatoi (Thailand).[14][22]
Like other mosquito species, only the females require a blood meal to develop their eggs. Apart from that, they feed on nectar and other sweet plant juices just as the males do. In regards to host location, carbon dioxide and organic substances produced from the host, humidity, and optical recognition play important roles.
The search for a host takes place in two phases. First, the mosquito exhibits a nonspecific searching behavior until it perceives host stimulants, whereupon it secondly takes a targeted approach.[23] For catching tiger mosquitoes with special traps, carbon dioxide and a combination of chemicals that naturally occur in human skin (fatty acids, ammonia, and lactic acid) are the most attractive.[24]
The Asian tiger mosquito particularly bites in forests during the day, so has been known as the forest day mosquito. Depending upon region and biotype, activity peaks differ, but for the most part, they rest during the morning and night hours. They search for their hosts inside and outside human dwellings, but are particularly active outside. The size of the blood meal depends upon the size of the mosquito, but it is usually around 2 μl. Their bites are not necessarily painful, but they are more noticeable than those from other kinds of mosquitoes. Tiger mosquitoes generally tend to bite a human host more than once if they are able to.[23][25]
Ae. albopictus also bites other mammals besides humans, as well as birds.[23][25] The females are always on the search for a host and are persistent but cautious when it comes to their blood meal and host location. Their blood meal is often broken off before enough blood has been ingested for the development of their eggs, so Asian tiger mosquitoes bite multiple hosts during their development cycle of the egg, making them particularly efficient at transmitting diseases. The mannerism of biting diverse host species enables the Asian tiger mosquito to be a potential bridge vector for certain pathogens that can jump species boundaries, for example the West Nile virus.
Primarily, other mosquito larvae, flatworms, swimming beetles, fungi, ciliates, paramecia, protozoans which act as parasites, predatory copepods, and spiders are natural enemies of the larval stage of Asian tiger mosquitoes.
Toxorhynchites larvae, a mosquito genus that does not suck blood, feeds upon other mosquito larvae and are often found with tiger mosquito larvae. Flatworms and small swimming beetles are considered natural predators.[25]
Fungi from the genus Coelomomyces (order Blastocladiales) develop inside the visceral cavity of mosquito larvae. The species Coelomomyces stegomyiae was first found on the Asian tiger mosquito.[25]
Paramecia, or ciliates, can also affect Ae. albopictus larvae, and the first detected species was Lambornella stegomyiae (Hymenostomatida: Tetrahymenidae).[25] The virulence, mortality rate, and subsequent possibilities of Lambornella being implemented as a biological remedy to control Ae. albopictus, however, has conflicting views.[26][27]
Sporozoans of the genus Ascogregarina (Lecudinidae) infect the larval stage of mosquitoes. The species Ascogregarina taiwanensis was found in Asian tiger mosquitoes.[25] When the adult mosquitoes emerge from their pupal case, they leave the infectious intermediary stage of parasites in the water and close off the infection cycle. Infected adults are generally smaller than non-infected adults and have an insignificantly higher mortality rate; therefore, food supply and larval density apparently play a role. In competitive situations, an infection with sporozoans can also reduce the biological fitness of other uninfected mosquitoes. However, the use of the parasites as an effective biological remedy to control mosquito populations is implausible because the host must reach the adult stage for the transmission of the parasites.[28]
Though they do not commonly occur in the natural habitats of Asian tiger mosquitoes, predatory copepods from the family Cyclopidae seem to willingly feed on them given the opportunity.[25] Relatives of different genera could therefore present a possibility in the control of tiger mosquitoes.[29]
Predators of adult Ae. albopictus in Malaysia include various spider species. Up to 90% of the gathered spiders from rubber plantations and a cemetery fed upon Asian tiger mosquitoes. Whether the spiders would have an effect on the mosquito population is still unclear. Tiger mosquitoes were abundantly present despite the existence of the spiders.[30]
The Asian tiger mosquito originally came from Southeast Asia. In 1966, parts of Asia and the island worlds of India and the Pacific Ocean were denoted as the area of circulation for the Asian tiger mosquito.[31] Ae. albopictus as a native of tropical and subtropical regions with warm and humid climate, is active all year long; however, it has been adapting successfully to cooler, temperate regions, where they hibernate over winter. Eggs from strains in the temperate zones are more tolerant to the cold than ones from warmer regions.[32][33] The species can even tolerate snow and temperatures under freezing. Adult tiger mosquitoes can survive throughout winter in suitable microhabitats.[34]
Since the mid-1960s, the tiger mosquito has spread to Europe, the Americas, the Caribbean, Africa, and the Middle East. As of 2008 Ae. albopictus was one of the 100 world's worst invasive species according to the Global Invasive Species Database.[35]
As of 2006, Ae. albopictus was not native to Australia and New Zealand.[36][37] The species was introduced there multiple times, but has yet to establish itself. This is due to the well-organized entomological surveillance programs in the harbors and airports of these countries. Nevertheless, as of 2006 it has become domestic on the islands in the Torres Strait between Queensland, Australia, and New Guinea.[38]
In Europe, Asian tiger mosquitos first emerged in Albania in 1979, introduced through a shipment of goods from China. In 1990–1991, they were most likely brought to Italy in used tires from Georgia (USA), and since then have spread throughout the entire mainland of Italy, as well as parts of Sicily and Sardinia. Since 1999, they have established themselves on the mainland of France, primarily southern France. In 2002, they were also discovered in a vacation town on the island of Corsica, but did not completely establish themselves there until 2005. In Belgium, they were detected in 2000 and 2013,[39] in 2001 in Montenegro, 2003 in Canton Ticino in southern Switzerland, and Greece, 2004 in Spain and Croatia, 2005 in the Netherlands and Slovenia, and 2006 in Bosnia and Herzegovina.[1] In the fall of 2007, the first tiger mosquito eggs were discovered in Rastatt (Baden-Wuerttemberg, Germany).[40] Shortly before, they were found in the northern Alps of Switzerland in Canton Aargau.[41] Since 2010, it has also been sighted increasingly in Malta during summer. In September 2016, Public Health England found eggs, though no mosquitos, in a lorry park at Folkestone service station on the M20, near Westenhanger, which is 6 miles West of the Eurotunnel.[42] The Swiss Autobahns are especially of concern.[43] Governments and universities in Switzerland cooperate every year to monitor the invasion using traps at Autobahn rest stations, and also at airports and commercial hubs.[43]
In the United States, this species invaded the Southern United States in the 1980s and rapidly spread northward into novel climate compared to its native range.[44] It was initially found in 1983 in Memphis, Tennessee.[45] then at the Port of Houston in a 1985 shipment of used tires,[46] and spread across the South up the East Coast to become prevalent in the Northeast.[47] It was not discovered in Southern California until 2001, then eradicated for over a decade; however, by 2011, it was again being found in Los Angeles County traps, then over the next two years expanded its range to Kern County and San Diego County.[48] [49][50] As of 2013, North American land favoring the environmental conditions of the Asian tiger mosquito was expected to more than triple in size in the coming 20 years, especially in urban areas.[51] As of 2017 Aedes albopictus mosquitoes have been identified in 1,368 counties in 40 U.S states.[52][53] A 2019 study in Nature Microbiology that modeled expansion of Aedes albopictus due to climate change, urbanization, and human movement found that the species would likely continue to spread throughout the coming decades.[54]
In Latin America, the Asian tiger mosquito was first discovered 1986 in Brazil[55] and in 1988 in Argentina and Mexico,[56] as well. Other parts of Latin America where the Asian tiger mosquito was discovered are the Dominican Republic in 1993, Bolivia, Cuba, Honduras, and Guatemala in 1995, El Salvador in 1996, Paraguay in 1999, Panama in 2002, and Uruguay and Nicaragua in 2003.[57]
In Africa, the species was first detected in 1990 in South Africa.[58] In Nigeria, it has been domestic since at least 1991.[59] It spread to Cameroon in 1999/2000,[60] to the Bioko Island of Equatorial Guinea in 2001,[61] and to Gabon in 2006.[62]
In the Middle East, the species was detected in Lebanon in 2003 and in Syria in 2005; the first record in Israel was published in 2003.[63]
Ae. albopictus can outcompete and even eradicate other species with similar breeding habitats from the very start of its dispersal to other regions and biotopes.[64] In Kolkata, for example, it was observed in the 1960s that egg depositing containers were being settled by the Asian tiger mosquito in city districts where the malaria mosquito (genus Anopheles) and yellow fever mosquito (Aedes aegypti) had both been eliminated by the application of DDT.[65] This may be because primarily the inner walls of the houses were treated with DDT to kill the mosquitoes resting there and fight the malaria mosquito. The yellow fever mosquito also lingers particularly in the inside of buildings and would have been also affected. The Asian tiger mosquito rests in the vicinity of human dwellings would therefore have an advantage over the other two species. In other cases where the yellow fever mosquito was repressed by the Asian tiger mosquito, for instance in Florida, this explanation does not fit.[66][67] Other hypotheses include competition in the larval breeding waters, differences in metabolism and reproductive biology, or a major susceptibility to sporozoans (Apicomplexa).[68]
Another species which was suppressed by the migrating Ae. albopictus was Ae. guamensis in Guam.[69]
The Asian tiger mosquito is similar, in terms of its close socialization with humans, to the common house mosquito (Culex pipiens). Among other differences in their biology, Culex pipiens prefers larger breeding waters and is more tolerant to cold. In this respect, no significant competition or suppression between the two species likely occurs.[68]
A possible competition among mosquito species that all lay their eggs in knotholes and other similar places (Ae. cretinus, Ae. geniculatus, and Anopheles plumbeus) has yet to be observed.
In Europe, the Asian tiger mosquito apparently covers an extensive new niche. This means that no native, long-established species conflict with the dispersal of Ae. albopictus.
Ae. albopictus is known to transmit pathogens and viruses, such as the yellow fever virus, dengue fever, Chikungunya fever,[2] and Usutu virus.[70] There is some evidence supporting the role of Ae. albopictus in the transmission of Zika virus, which is primarily transmitted by the related Ae. aegypti.[5]
The Asian tiger mosquito was responsible for the Chikungunya epidemic on the French Island La Réunion in 2005–2006. By September 2006, an estimated 266,000 people were infected with the virus, and 248 fatalities occurred on the island.[71] The Asian tiger mosquito was also the transmitter of the virus in the first and only outbreak of Chikungunya fever on the European continent. This outbreak occurred in the Italian province of Ravenna in the summer of 2007, and infected over 200 people.[72][73] Evidently, mutated strains of the Chikungunya virus are being directly transmitted through Ae. albopictus particularly well and in such a way that another dispersal of the disease in regions with the Asian tiger mosquito is feared.[74]
On the basis of experimental evidence and probability estimates, the likelihood of mechanical or biological transmission of HIV by insects is virtually nonexistent.[75]
The tiger mosquito is relevant to veterinary medicine. For example, tiger mosquitoes are transmitters of Dirofilaria immitis, a parasitic roundworm that causes heart failure in dogs and cats.[76]
Wolbachia infection are the most common infection in arthropods today, and over 40% of arthropods have contracted it.[77] Wolbachia can be transmitted from parent to offspring or between breeding individuals. Wolbachia is easily transmitted within the Ae. albopictus mosquito due to the effects it has on fecundity in females.[78] Once female Asian tiger mosquitos have contracted the infection, they produce more eggs, give birth more frequently, and live longer than uninfected females. In this way, Wolbachia provides a fitness advantage to the infected females and prevents uninfected females from reproducing. This allows control of the spread of diseases that many species carry by suppressing reproduction of the individuals with the harmful disease, but without the Wolbachia infection. Wolbachia can also be used to transfer certain genes into the population to further control the spread of diseases.[79]
In the natural environment, Wolbachia and the Asian tiger mosquito are in a symbiotic relationship, so both species benefit from each other and can evolve together. The relationship between Wolbachia and its host might not have always been mutualistic, as Drosophila populations once experienced decreased fecundity in infected females, suggesting that Wolbachia evolved over time so that infected individuals would actually reproduce much more.[80] The mechanism by which Wolbachia is inherited through maternal heredity is called cytoplasmic incompatibility.[78] This changes the gamete cells of males and females, making some individuals unable to mate with each other. Although little is known about why cytoplasmic incompatibility exists, Wolbachia infection creates a fitness advantage for infected females, as they can mate with either infected or uninfected males. Despite this, infected males cannot reproduce with uninfected females. Therefore, over time, a population exposed to Wolbachia transitions from a few infected individuals to all individuals becoming infected, as the males that cannot reproduce successfully do not contribute to future generations. This is called population replacement, where the population's overall genotype is replaced by a new genotype. This shows how populations of Asian tiger mosquitoes can vary in number of Wolbachia-infected individuals, based on how often the infection is transmitted.[81] Due to Wolbachia's ability to transmit from one host to the next, it can change the average genotype of a population, potentially reducing the population's gene flow with other nearby populations.
This type of cytoplasmic incompatibility where an infected male cannot reproduce successfully with an uninfected female is called unidirectional cytoplasmic incompatibility. It occurs because Wolbachia modifies the paternal chromosomes during sperm development, leading to complications for these offspring during embryonic development.[82]
Also, bidirectional cytoplasmic incompatibility occurs when an infected male carrying one strain of Wolbachia reproduces with an infected female carrying a different strain of Wolbachia. This also results in failed reproduction, this incompatibility also has evolutionary implications for populations of Ae. albopictus and other vectors of the infection.[83] This is because bidirectional cytoplasmic incompatibility in Wolbachia creates unviable offspring, reducing gene flow between two populations, which can eventually lead to speciation.
Ae. albopictus is very difficult to suppress or to control due to its remarkable ability to adapt to various environments, its close contact with humans, and its reproductive biology.
The containment of infestations is generally effected by public health services through area-wide integrated control plans, which aim to reduce the nuisance perceived by populations and the risks of viraemic transmission. Such plans consist of different activities that include entomological surveillance, larvicide treatments in public and private areas, information campaigns, and treatments against adult mosquitoes in the zones affected by suspected cases of transmissible viruses.[84]
Efficient monitoring or surveillance is essential to prevent the spread and establishment of this species. In addition to the monitoring of ports, warehouses with imported plants, and stockpiles of tires, rest areas on highways and train stations should be monitored with appropriate methods.[85]
The control of Asian tiger mosquitoes begins with destroying the places where they lay their eggs, which are never far from where people are being bitten, since they are weak fliers, with only about a 180 m (650 ft) lifetime flying radius. Puddles that last more than three days, sagging or plugged roof gutters, old tires holding water, litter, and any other possible containers or pools of standing water should be drained or removed. Bird baths, inlets to sewers and drainage systems holding stagnant water, flower pots, standing flower vases, knotholes, and other crevices that can collect water should be filled with sand or fine gravel to prevent mosquitoes from laying their eggs in them.
Any standing water in pools, catchment basins, etc., that cannot be drained, or dumped, can be periodically treated with properly labeled insecticides or Bacillus thuringiensis israelensis (Bti), often formed into doughnut-shaped "mosquito dunks". Bti produces toxins which are effective in killing larvae of mosquitoes and certain other dipterans, while having almost no effect on other organisms. Bti preparations are readily available at farm, garden, and pool suppliers.
Flowing water will not be a breeding spot, and water that contains minnows is not usually a problem, because the fish eat the mosquito larvae.
Dragonflies are also an excellent method of control. Dragonfly larvae eat mosquito larvae in the water, and adults snatch adult mosquitoes as they fly.
In any case, an efficient surveillance is essential to monitor the presence of tiger mosquitoes and the effect of control programs. Ovitraps are normally used for the monitoring of Ae. albopictus. They are black water containers with floating Styrofoam blocks or small wooden paddles that are in contact with the surface of the water. Female tiger mosquitoes lay their eggs on these surfaces. Through the identification of these eggs or of the larvae that hatch from these eggs in the laboratory, the presence and abundance of mosquito species can be estimated. Versions of these traps with an adhesive film (sticky traps) that catch the egg-depositing mosquitoes make the analysis much easier and quicker, but are more complicated in terms of handling.[86][87] The results of ovitraps are often variable and depend on the availability of alternative egg-depositing waters. Due to this, it is best to use them in large numbers and in conjunction with other monitoring methods.
To date, few effective traps for adult Asian tiger mosquitoes are available. Those traps that catch other species of mosquitoes do not catch tiger mosquitoes efficiently. A form of an ovitrap called a lethal ovitrap mimics the breeding site for Ae. albopictus just like the monitoring tool, but it has the added benefit of containing chemicals that are toxic to the mosquitoes when they enter, but do not harm humans. These traps have had success in some countries to control Aedes mosquito populations.[88] A new trap type has now been shown to catch significant numbers of Ae. albopictus.[89][90] This device, with the help of a ventilator, produces an upward air current of ammonia, fatty acids, and lactic acids that takes a similar form and smell of a human body. With the addition of carbon dioxide, the efficacy of the trap is increased. This means a suitable tool is available for trapping adult tiger mosquitoes, and for example, examining the existence of viruses in the trapped mosquitoes. Previously, the mosquitoes had to be collected from volunteers to be studied, which is ethically questionable, especially during epidemics. Recent research also indicates this trap type may also have a use as a control tool; in a study in Cesena, Italy, the number of biting tiger mosquitoes was reduced in places where traps were installed.[91]
An amino acid substitution mutation – F1534C – is overwhelmingly the most common voltage-gated sodium channel in A. albopictus in Singapore.[92] This channel as the target of pyrethroids,[92] is suspected to be a knockdown resistance (kdr) mutation,[92] and that is the reason for its prevalence.[92]
Although the Wolbachia infection is prevalent in arthropod species, especially the Asian tiger mosquito, it is a useful mechanism for inhibiting the spread of dengue.[93] Ae. aegypti individuals, a close relative of Ae. albopictus, with an artificial Wolbachia infection, cannot transmit dengue, an infectious virus, but they can pass on the Wolbachia infection to other populations. This could lead to many more discoveries in disease control for Ae. albopictus and other mosquito species.[93] In addition, due to the cytoplasmic incompatibility caused by Wolbachia, the artificial infection of males can serve as a biological control as they are unable to reproduce successfully with uninfected females (unidirectional CI).[82] When artificially infected males are unable to reproduce, the population size can be controlled, thereby reducing the transmission of the harmful disease of interest. Artificial infection of males is achieved by the removal of cytoplasm from infected oocytes, which is then transferred into embryos prior to the blastoderm stage.
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(help) Aedes albopictus (Stegomyia albopicta), from the mosquito (Culicidae) family, also known as the (Asian) tiger mosquito or forest mosquito, is a mosquito native to the tropical and subtropical areas of Southeast Asia. In the past few centuries, however, this species has spread to many countries through the transport of goods and international travel. It is characterized by the white bands on its legs and body.
This mosquito has become a significant pest in many communities because it closely associates with humans (rather than living in wetlands), and typically flies and feeds in the daytime in addition to at dusk and dawn. The insect is called a tiger mosquito for its striped appearance, which resembles that of the tiger. Ae. albopictus is an epidemiologically important vector for the transmission of many viral pathogens, including the yellow fever virus, dengue fever, and Chikungunya fever, as well as several filarial nematodes such as Dirofilaria immitis. Aedes albopictus is capable of hosting the Zika virus and is considered a potential vector for Zika transmission among humans.