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australia:mosquitoes

Mosquitoes in Australia

Introduction

  • mosquitoes are prevalent in most areas of Australia and belong to the insect family Culicidae
  • fortunately, malaria is not found in Australia, and dengue fever is limited to the tropics such as around Cairns carried by Aedes aegypti.
  • also very fortunately, Aedes albopictus (tiger mosquito) has not yet invaded Australia although it is in Torres Strait1) and as it can tolerate cooler climates could eventually spread across Australia and bring dengue, zika and chikungunya viruses even to Victoria as it has down in most other parts of the world, and also tends to bite throughout the day.
  • nevertheless, mosquitoes in Australia can spread viral diseases such as Ross River virus and bites should be avoided where possible.
  • there are more than 275 mosquito species in Australia. Only a few species bite humans, and even less carry human diseases.
  • only the females feed on blood which they need to develop eggs which are generally hatched some 48hrs after a feed
  • males only live about 1 week and feed on plant nectar
  • females can live to around 28 days although less than 10% of mosquitoes survive more than 10 days as adults.
  • the life cycle of eggs hatching through to adult form takes 7-14 days with the eggs generally hatching after contact with water and eggs can survive many months of drought
    • they can tolerate organically polluted water such as septic tanks, drains, sludge pits, ground water at garbage dumps, as well as brackish water such as estuarine marshes and swamps, tidal reaches of river margins and irrigation run-off in inland areas with saline soil.
  • some species only remain near where they hatch, others travel a km or two, whereas other species can travel up to 50km downwind
  • female adults are generally most active at dawn and dusk when the air is more humid and the insects are at less risk of drying out, and will seek blood sources depending upon a range of stimuli including carbon dioxide levels, body odour, air movement or heat
  • one the female has fed they will generally rest to digest her meal and develop eggs.
  • in Victoria, mosquito numbers tend to increase after rains in Winter/Spring followed by a warm Spring
  • most species disappear over winter

pest species which bite humans in Victoria

  • there are two primary mosquito species which play a major role in Ross river Virus (RRV) transmission in Victoria these include: Aedes camptorhynchus and Culex annulirostris. Macropod marsupials are generally regarded as key reservoir species, making Eastern Grey kangaroos (Macropus giganteus) and possums (Trichosurus vulpecula) likely reservoirs and juvenile susceptible hosts amplify transmission more so than high mosquito populations 2)

major pests

  • Aedes alternans: nuisance pest in many areas and noticed because of its size; can carry Ross River; vicious biters of humans and other animals, biting by day and night; may disperse several kilometres from larval habitat. The larval stage is predacious on other mosquito larvae.
  • Aedes camptorhynchus: a major pest in coastal areas of Vic, Tas and parts of SA; can carry Ross River virus and this has been found in E. Gippsland and east coast Tas. can be vicious biters readily attacking humans and other animals including birds, and will feed during the day, at dusk and after sunset.
  • Aedes notoscriptus: arguably the major domestic pest species in southeastern Australia; can carry MVE, Ross River and Barmah viruses; readily attack humans by day in shaded areas but also feed during evening, night and early morning.
  • Aedes rubrithorax: (NSW, QLD, SA, TAS, WA, VIC) more common in coastal areas than the inland. It breeds in a variety of groundpools and creekline rockpools. Can be a pest in or near some bushland areas.
  • Aedes sagax: (NSW, QLD, SA, VIC, WA) a large mosquito from inland regions, and can be a major pest after flooding in summer and autumn. can carry MVE and Ross river viruses;
  • Aedes theobaldi: Can be a significant pest in irrigation areas and after floods in rural riverine areas in Murray River regions; can carry MVE and Ross river viruses; day-biting is usually apparent as the species readily attacks humans and other animals but they will bite also in the evening and at night.
  • Aedes vittiger: Can be a significant pest in irrigation areas and after floods in rural riverine areas in Murray River regions; can carry MVE;
  • Culex molestus (“London Underground Mosquito” probably arrived in Victoria in WWII with returning soldiers): can be a serious domestic pest indoors in certain areas; can carry MVE; bites at night; can be active all year round.
  • Culex quinquefasciatus: This is the major domestic pest in many urban areas, particularly as indicated by indoor biting but is mainly north of Central Highlands and into NSW. Can carry MVE. Bites in middle of the night.

can be nuisance

  • Aedes alboannulatus: (all states) a commonly collected mosquito, particularly early or late in the mosquito season. The larvae are found in bushland ground pools and creekline rockpools. Can be a pest in bushland areas,
  • Aedes bancroftianus: (NSW, NT, QLD, SA, VIC, WA) common mosquito in inland regions, and can be a nuisance after flooding or extensive rain. can carry Ross river and barmah;
  • Aedes flavifrons: (NSW, southern QLD, SA, TAS, VIC) a large and sometimes common mosquito that breeds in bushland groundpools and can be a nuisance biter. Ross River virus has been isolated from this species but it is not thought to be a major pest.
  • Tripteroides atripes: (all states) collected occasionally from both inland and coastal regions, this species breeds in both natural (tree hole) and artificial containers. Can be a nuisance pest in some rural areas, but vector status unknown.

not usually a serious pest

  • Aedes dobrotworskyi: (NSW, VIC) found in association with sword grass.
  • Aedes nivalis: (NSW, TAS, VIC) a cold-tolerant highlands mosquito; even found in the Mt Kosciuszko area. It will bite humans, but is not often a problem
  • Aedes procax: (NSW, QLD, VIC) a common species in coastal regions and breeds in bushland groundpools. Can be a minor pest close to its breeding area, and Ross River & Barmah Forest viruses have been isolated from this species.
  • Aedes tremulus: (NSW, NT, QLD, SA, VIC, northern WA) a small species that breeds in treeholes (and artificial containers). Ross River, Kunjin & Murray Valley Encephalitis viruses have been isolated from the mosquito
  • Aedes wattensis: (NSW, NT, QLD, SA, VIC) an uncommon very small, stoutly built mosquito from inland areas. Little is known about its ecology but it probably is a tree-hole breeder. It will bite humans, but is not a significant pest and its vector status is unknown
  • Anopheles annulipes: only rarely a pest even when relatively abundant as it does not preferentially attack humans but rather bites cattle. Bites at night and could carry MVE, Ross River and even malaria.
  • Tripteroides marksae: (NSW, QLD, VIC) a smallish mosquito with a very long proboscis. Larvae breed in both natural and artificial containers. Adults are known to attack humans but rarely are they considered a serious pest. Vector status unknown.
  • Tripteroides tasmaniensis: (NSW, southeast QLD, SA, TAS, VIC) an uncommon species that breeds in natural and artificial containers. Adults are known to attack humans, mostly during the day, but rarely are they considered a serious pest. Vector status unknown
australia/mosquitoes.txt · Last modified: 2021/04/01 23:30 by gary1