Arthropoda

Taxonomic level: Phylum
Displaying 21 - 30 of 59

Anopheles farauti

Image: 
Anopheles farauti
Body: 

Range

Anopheles farauti is a complex of seven species distributed in the Moluccas (Indonesia) and extend eastward through Papua New Guinea (the Admiralty Islands and the Bismarck Archipelago), the Solomon Islands, the New Hebrides (Vanuatu) and Australia. Anopheles farauti sensu stricto (formerly A. farauti 1) is distributed in Papua New Guinea and Australia where it is and it was a malaria vector, respectively.

Habitats

Collectively, the Farauti Complex shows an ability to use a great variety of aquatic habitats,. with selection dependent on habitat availability and influenced by dry and wet season precipitation patterns. Sites can be shaded or sunlit but usually consist of open areas away from heavy shade (canopy). The complex, being large and ecologically diverse, can utilise tidal and coastal brackish zones and a variety of inland fresh-water sites. In general, relatively little is known definitively about the ecology and behaviour of most of the species in the Farauti Complex but salinity tolerance appears to be a major factor in species distribution within this Complex. For example, An. hinesorum has far less tolerance for salinity than An. farauti and appears restricted to inland freshwater locations. However, the degree of tolerance may be variable within a species range. An. farauti s.s. is predominately found within 1 km of coastal areas and is replaced by other members in the Complex further inland. An. irenicus shares the high salt-tolerance capabilities of An. farauti s.s. however, it is only found in freshwater habitats. Larvae of An. farauti s.l. are commonly found in natural, rain-fed temporary pools to larger semi-permanent to permanent bodies of ground water, usually with some varying degree of floating or emergent vegetation (e.g. Ipomoea aquatica). They also sometimes occur in artificial containers, drums, coconut shells, canoes and other unusual habitats. An. farauti s. s. can occupy brackish water pools high in organic debris and subject to tidal fluctuations in areas where vast stretches of mangroves occupy the coastline. Natural sites ranging from swamps (non-peat), dead river arms (oxbows) and open river flats to artificial sites including fish ponds and large ditches, burrow pits, pig wallows, garden pools and pools created along stream and river margins. An. farauti s.s. is sometimes found with An. punctulatus even though it generally prefers more undisturbed habitats.

Resting and feeding preferences

Adult members of the Complex appear to exhibit a preference for certain hosts in different regions. The time of peak biting activity also varies by locality. The heterogeneous behavioural patterns are related to differences between the individual species of the complex. Anopheles irenicus is not anthropophilic whereas An. farauti s.s. readily bites humans. Feeding of An. farauti s.l. is mainly nocturnal and continues throughout the evening, however, daytime biting can occur. Although females will feed on birds and mammals, and when near human habitation, will often feed on domestic dogs, pigs and cattle, they have a higher preference for biting humans in most areas. Host preference also appears to depend on the availability of host types. Adult females will readily attack humans inside and outside houses. Indoor resting behaviour occurs before and after feeding, but habits are varied. Individuals that feed inside houses may rest indoors for a period of time but the majority will exit before dawn to rest outdoors. Daytime resting sites include cool, damp and darkened places near ground level. Daytime indoor resting has also been observed. Feeding frequency and peak activity is variable by locality and influenced by prevailing conditions and season, with some areas recording fairly uniform biting throughout the night. Other locations have seen peaks around or after midnight with other sites showing the majority of biting occurring before midnight. Early evening peaks have also been recorded in some localities.

Vectorial capacity

An. farauti s.s., An. hinesorum and An. farauti No. 4 are considered to be important malaria vectors. An. farauti s.s. is an important vector in the Solomon Islands and the islands of Buka and Bougainville, Papua New Guinea. A newly identified taxon, tentatively named An. farauti No. 8 has also been incriminated as a vector of malaria in Papua New Guinea, and An. farauti No. 6 appears, based on circumstantial evidence, to be a major vector in the highland river valleys and intramontane plains of New Guinea up to 2000m or higher. An. irenicus is not considered to have an important role in malaria transmission.

Short Name: 
afarauti
Organism taxonomy: 

Anopheles freeborni

Image: 
Anopheles freeborni
Body: 

Anopheles freeborni, the Western malaria mosquito, is found in western Canada and in the United States. This species is the principal malaria vector in the arid and semiarid western U.S. (Carpenter and LaCasse 1955).

Short Name: 
afreeborni
Organism taxonomy: 

Anopheles funestus

Image: 
Anopheles funestus
Body: 

Range

Anopheles funestus has a wide geographic distribution, extending throughout Africa where is one of the most important vectors of malaria.

Habitats

A typical An. funestus larval habitat is a large, permanent or semi-permanent body of fresh water with emergent vegetation, such as swamps, large ponds and lake edges. Larvae have been found in shaded and sunlit environments where An. funestus may use emergent vegetation as refuge against predation while the shading it casts, or the presence of shade from overhanging plants, is of lesser importance. In some areas, An. funestus larvae are associated with rice cultivation (e.g. Madagascar, Mali) and replaces An. arabiensis in a successive temporal process during rice plant growth, exhibiting higher densities in older, maturing fields compared to the preceding open conditions preferred by An. arabiensis. An. funestus is a highly adaptable species, allowing it to occupy and maintain its wide distribution and utilise and conform to the many habitat types and climatic conditions contained therein.

Resting and feeding preferences

An. funestus is considered to be highly anthropophilic. Behaviourally, its late-night biting patterns potentially allows ready access to human blood without incurring undue density-dependant host avoidance. This late-night biting preference is clearly evident throughout its range, with peak biting period generally occurring after 22:00, commonly between midnight and the early hours of the morning. Endophilic resting behaviour is also commonly reported, allowing successful vector control using indoor residual spraying and insecticide-treated nets. However, insecticide exposure has resulted in selection pressure and rapid development of insecticide resistance to pyrethroids, now well established in some populations. Compared to other dominant vector species in Africa, An. funestus shows fairly consistent behaviour (generally anthropophilic and endophilic) throughout its range but some behavioural differences have been reported. For example, anthropophilic behaviour has been found in western Senegal and zoophilic behaviour in the east of the country.

Vectorial capacity

An. funestus is regarded as an important vector of malaria. The endophilic resting behaviour of An. funestus combined with a relatively high longevity, makes it as good a vector, or better in some areas, as An. gambiae. Insecticide resistance to pyrethroids, now well established in some An. funestus populations, has been implicated as the primary reason for a major resurgence of epidemic malaria reported in Kwazulu- Natal, South Africa in the late 1990s.

This text was modified from Sinka ME et al. (2010) The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis Parasites & Vectors 3:117.

Short Name: 
afunestus
Organism taxonomy: 

Anopheles koliensis

Body: 

Anopheles koliensis belongs to the Anopheles punctulatus species complex and is distributed throughout SW Pacific region namely Indonesia, Papua Island, Papua New Guinea, and the Solomon Islands. An. koliensis is a primary vector of malaria and periodic filiariasis vector. Larvae are found in temporary pools in grassland areas in full sunlight. Females are night biters and strongly anthropophilic (Belkin 1962).

Short Name: 
akoliensis
Organism taxonomy: 

Anopheles maculatus

Image: 
Anopheles maculatus
Body: 

Range

Anopheles maculatus complex includes important malaria vectors distributed from the Indian subcontinent through Southeast Asia to Taiwan. Anopheles maculatus B is a vector member of this complex.

Habitats

Members of the Maculatus Group are typically found in or near hilly and mountainous areas. Larvae have been collected in a diverse number of permanent or semi-permanent bodies of clean water that are often exposed to direct sunlight, including ponds, lakes, swamps, ditches, wells, different types of pools (grassy, sandy, ground, flood, stream), margins along small, slow-flowing streams, gravel pits along stream margins, seepages, springs, rice fields, foot and wheel prints, and occasionally tree holes and bamboo stumps. More specific studies have shown that each species has a preferred habitat. For instance, larvae of An. willmori are found only along stream margins at altitudes between 990m and 1450m in northern Thailand, whereas larvae of An. pseudowillmori have been collected primarily in rice fields, stream margins, ponds, pits and wells. An. maculatus prefers to use pools of water formed on the banks of rivers and waterfalls most commonly shallow pools 5-15cm deep with clear water, mud substrate and emergent plants. This species also requires, or strongly prefers, open to partially shaded habitats. Habitats are commonly located at 100m to 400m from the nearest human settlement.

Resting and feeding preferences

In general, females are more strongly attracted to cattle than humans, but freely bite people both inside and outside houses. An. maculatus and An. sawadwongporni appear to be the least zoophilic of the species and exhibit early biting activity, peaking between 18:00 and 21:00. An. dispar and An. greeni exhibit strong exophagic and zoophilic behaviours. The combination of the early evening biting activity of these malaria vectors (particularly An. maculatus and An. sawadwongporni) and their zoophilic and exophilic tendencies indicates that they will be less affected by vector control methods based on indoor residual spraying and insecticide-treated bed nets. However, a strategy of creating a barrier using insecticide on vegetation near cattle or other animal hosts may provide significant in the control of these vectors.

Vectorial capacity

Members of the Maculatus Group are variously involved in malaria transmission. However, the vector role of each species is not precisely known and their vectorial capacity appears to vary depending on geographical location. An. maculatus has the widest distribution of all species of the group but it is only an important vector of human malarial parasites in hilly areas of eastern India, southern Thailand, peninsular Malaysia and south-central Java. Anopheles sawadwongporni is considered an important vector in Thailand and An. pseudowillmori is a secondary vector in northwestern Thailand along the Myanmar border. Anopheles. willmori is one of the primary vectors in Nepal, but it is seldom collected in Thailand and does not appear to be involved in malaria transmission there. Anopheles dispar and An. greeni are regarded as secondary vectors in the Philippines. Anopheles notanandai, An. dravidicus and An. rampae are not known to be involved in malaria transmission.

This text was modified from Sinka ME et al. (2011) The dominant Anopheles vectors of human malaria in Asia-Pacific: occurrence data, distribution maps and bionomic précis Parasites & Vectors 4:89.

Short Name: 
amaculatus
Organism taxonomy: 

Anopheles melas

Body: 

Range

Anopheles melas belongs to the Anopheles gambiae species complex, which consists of at least seven species, and it is a locally important vector in coastal western Africa.

Habitats

An. melas is commonly associated with brackish water and can utilise saline environments, yet does not appear to require brackish water for larval stage development. It is generally restricted to coastal areas but has been found up to 150km inland along the Gambia River, where salt water can intrude great distances (up to 180km) upriver. Unlike other African dominant vector species, the density fluctuations of An. melas are closely associated with tidal changes rather than seasons, and a peak in adult numbers 11 days after spring tides has been recorded. The larvae of this species are associated with salt marsh grass (Paspalum species) and mangroves, but only those of the genus Avicenna, which include white, grey and black mangrove, and not from the genus Rhizophora (’true’ or red mangrove spp.). These positive and negative associations are thought to be strongly influenced by the predominant soil type associated with the different tree genera, The poorly drained, peaty-like soil common to Avicenna forests appears preferable to An. melas compared to the sandy, gravelly or smooth, fibrous peat soils common to the Rhizophora stands. An. melas oviposits on damp ground at low tide rather than in open water, and the eggs are able to survive some degree of desiccation until the tides rise again. This behaviour may guarantee the larvae will have sufficient time to complete their larval development and pupate in the less saline, relatively permanent waters of the new tide before it begins to recede and the water either becomes too salty, or dries out completely.

Resting and feeding preferences

Adult biting behaviour appears to be opportunistic. An. melas has been described as both highly anthropophilic and a zoophilic species and has been shown to be fairly indiscriminate in host choice. An. melas generally rests outdoors after feeding, although there has been limited success in locating and collecting from such natural outdoor resting sites. Those females that do bite and rest indoors are more likely to have fed on humans whereas those biting or resting outdoors (or in animal sheds) are more likely to have bitten animals. Blood feeding activity appears to be fairly continuous throughout the night.

Vectorial capacity

An. melas is generally considered to be a vector of lesser importance where it occurs in in the same places as An. gambiae or An. arabiensis. However, in coastal areas, where it can occur in very high densities, it is still a problematic vector of malaria.

This text was modified from Sinka ME et al. (2010) The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis Parasites & Vectors 3:117.

Short Name: 
amelas
Organism taxonomy: 

Anopheles merus

Image: 
Anopheles merus
Body: 

Range

Anopheles merus belongs to the Anopheles gambiae species complex, which consists of at least seven species, and it is a locally important vector in eastern and southern Africa where it is mainly found along the coast.

Habitats

An. merus is found in high numbers in shallow brackish pools and marsh or swamp areas along the coast. As a consequence, this species does not exhibit density changes in response to tidal fluctuations nor does it appear to tolerate very high levels of salinity. It is rarely found in the mangrove forests on the east coast of Africa, however this may be due to the composition of the trees and soil type under of the stands of mangrove in this zone rather than inherent behavioural patterns. An. merus is known to occur inland, using salt pans and saline pools as larval habitats.

Resting and feeding preferences

An. merus is generally opportunistic in host selection, depending on host availability and females have a tendency to bite and rest outdoors. The biting times of An. merus on the Kenyan coast have been reported as gradually rising from early evening (18:00) peaking between midnight and 01:00 and then declining until 06:00, which reflects the accepted biting pattern for this species across its range.

Vectorial capacity

An. merus has previously been considered as only a minor or unimportant vector, however, it has been identified as playing an unexpectedly important role along the Tanzanian coast and more recently in Mozambique.

This text was modified from Sinka ME et al. (2010) The dominant Anopheles vectors of human malaria in Africa, Europe and the Middle East: occurrence data, distribution maps and bionomic précis Parasites & Vectors 3:117.

Short Name: 
amerus
Organism taxonomy: 

Anopheles nili

Body: 

Anopheles nili is distributed throughout Sub-Saharan Africa and is an important vector in West Africa. An. nili has been reported with both feeding and resting habits it is anthropophilic species biting man readily indoors and outdoors and frequently resting indoors by day. It is a stream breeder, larvae being found in vegetation or in dense shade along the edges of streams and large rivers.

Short Name: 
anili
Organism taxonomy: 

Anopheles punctulatus

Body: 

Anopheles punctulatus belongs to the Anopheles punctulatus species complex and is distributed throughout SW Pacific region including Australia, Indonesia, New Guinea (Island) - Papua New Guinea, and the Solomon Islands. An. punctulatus is a primary vector of malaria and periodic filiariasis vector. Larvae are found in sunny road ruts and temporary pools. Females bite indoors during the early morning hours (Belkin 1962)

Short Name: 
apunctulatus
Organism taxonomy: 

Anopheles quadriannulatus

Image: 
Anopheles quadriannulatus A
Body: 

Anopheles quadriannulatus A belongs to the Anopheles gambiae species complex, which consists of at least seven species, it is found in southern Africa and is not considered to be a malaria vector.

Short Name: 
aquadriannulatusa
Organism taxonomy: 

Pages

Subscribe to Arthropoda