View source for Anopheles

{{short description|Genus of mosquito}}
{{good article}}
{{cs1 config|name-list-style=vanc}}
{{automatic taxobox
| image = Anopheles stephensi.jpeg
| image_caption = ''[[Anopheles stephensi]]'', female
| taxon = Anopheles
| authority = [[Johann Wilhelm Meigen|Meigen]] 1818
| subdivision_ranks = Species
| subdivision = For a full description, see the main article: [[Taxonomy of Anopheles]]
}}

'''''Anopheles''''' ({{IPAc-en|ə|ˈ|n|ɒ|f|ᵻ|l|iː|z}}) is a [[genus]] of [[mosquito]] first described by the German [[entomologist]] [[Johann Wilhelm Meigen|J. W. Meigen]] in 1818, and are known as '''nail mosquitoes''' and '''marsh mosquitoes'''.<ref name="USFWS">{{cite web |title=Nail Mosquito |url=https://www.fws.gov/species/nail-mosquito-anopheles |publisher=[[United States Fish and Wildlife Service]] |access-date=16 December 2023 |quote=Common Name: Nail Mosquito, marsh mosquitoes}}</ref> Many such mosquitoes are [[Disease vector|vectors]] of the parasite ''[[Plasmodium]]'', a genus of protozoans that cause [[malaria]] in [[Plasmodium species infecting birds|birds]], [[Plasmodium species infecting reptiles|reptiles]], and [[Plasmodium species infecting mammals other than primates|mammals]], including humans. The ''[[Anopheles gambiae]]'' mosquito is the best-known species of marsh mosquito that transmits the ''[[Plasmodium falciparum]]'', which is a malarial [[Parasitism|parasite]] deadly to human beings; no other mosquito genus is a vector of human malaria.

The genus ''Anopheles'' diverged from other mosquitoes approximately {{Ma|100}} ([[myr|mya]]), and, like other mosquitoes, the eggs, [[larva]]e, and [[pupa]]e are [[Aquatic animal|aquatic]]. The ''Anopheles'' larva has no respiratory siphon through which to breathe, so it breathes and feeds with its body horizontal to the surface of the water. The adult mosquito hatches from the surface and feeds on the nectar of flowers; the female mosquito also feeds on blood, which animal diet allows them to carry and transmit parasites between hosts. The adult's feeding position is head-down, unlike the horizontal stance of the culicines. ''Anopheles'' are distributed almost worldwide, throughout the tropics, the subtropics, and the temperate regions of planet Earth. In hot weather, adult ''Anopheles'' [[aestivate]], which is a state of dormancy that enables the mosquito to survive in hot dry regions, such as the [[Sahel]].

== Evolution ==
=== Fossil history ===
[[Fossil]]s of the genus ''Anopheles'' are rare; only two had been found by 2015.<ref name="Freitas Russo Voloch Mutaquiha 2015"/> They are ''Anopheles (Nyssorhynchus) dominicanus'' <small>Zavortink & Poinar</small> in Dominican Republic [[amber]] from the Late [[Eocene]] ({{Ma|40.4}} to {{Ma|33.9}}),<ref name="Zavortink Poinar 2000">{{cite journal |last1=Zavortink |first1=Thomas J. |last2=Poinar |first2=George O. |title=Anopheles (Nyssorhynchus) dominicanus sp. n. (Diptera: Culicidae) from Dominican Amber |journal=Annals of the Entomological Society of America |volume=93 |issue=6 |date=2000-11-01 |doi=10.1603/0013-8746(2000)093[1230:ANDSND]2.0.CO;2 |pages=1230–1235|s2cid=86221732 }}</ref> and ''[[Anopheles rottensis]]'' <small>Statz</small> in [[Germany|German]] amber from the Late [[Oligocene]] ({{Ma|28.4}} to {{Ma|23.0}}).<ref name="Freitas Russo Voloch Mutaquiha 2015">{{cite journal |last1=Freitas |first1=Lucas A. |last2=Russo |first2=Claudia A. M. |last3=Voloch |first3=Carolina M. |last4=Mutaquiha |first4=Olívio C. F. |last5=Marques |first5=Lucas P. |last6=Schrago |first6=Carlos G. |title=Diversification of the Genus Anopheles and a Neotropical Clade from the Late Cretaceous |journal=PLOS ONE |volume=10 |issue=8 |date=2015-08-05 |pmid=26244561 |pmc=4526650 |doi=10.1371/journal.pone.0134462 |article-number=e0134462 |bibcode=2015PLoSO..1034462F |doi-access=free }}</ref>

=== Phylogeny ===

The ancestors of all [[Fly|flies]] including mosquitoes appeared {{Ma|260}}.<ref name="Moreno Marinotti Krzywinski Tadei 2010">{{cite journal |last1=Moreno |first1=Marta |last2=Marinotti |first2=Osvaldo |last3=Krzywinski |first3=Jaroslaw |last4=Tadei |first4=Wanderli P. |last5=James |first5=Anthony A. |last6=Achee |first6=Nicole L. |last7=Conn |first7=Jan E. |title=Complete mtDNA genomes of ''Anopheles darlingi'' and an approach to anopheline divergence time |journal=Malaria Journal |volume=9 |issue=1 |date=2010 |page=127 |pmid=20470395 |pmc=2877063 |doi=10.1186/1475-2875-9-127 |doi-access=free}}</ref> The [[Culicinae|culicine]] and ''Anopheles'' clades of mosquitoes diverged between {{Ma|120}} and {{Ma|150}}.<ref name="Moreno Marinotti Krzywinski Tadei 2010"/><ref name="Calvo 2009">{{cite journal |author1=Calvo, Eric |author2=Pham, Van M. |author3=Marinotti, Osvaldo |author4=Andersen, John F. |author5=Ribeiro, José M. C. |year=2009 |title=The salivary gland transcriptome of the neotropical malaria vector ''Anopheles darlingi'' reveals accelerated evolution of genes relevant to hematophagy |journal=[[BMC Genomics]] |volume=10 |issue=1 |page=57 |doi=10.1186/1471-2164-10-57 |pmc=2644710 |pmid=19178717 |doi-access=free}}</ref> The Old and New World ''Anopheles'' species subsequently diverged between {{Ma|80}} and {{Ma|95}}.<ref name="Moreno Marinotti Krzywinski Tadei 2010"/><ref name="Calvo 2009"/> ''[[Anopheles darlingi]]'' diverged from the African and Asian malaria vectors ~{{Ma|100}}.<ref name="Neafsey Waterhouse Abai 2015">{{cite journal |last1=Neafsey |first1=Daniel E. |last2=Waterhouse |first2=Robert M. |last3=Abai |first3=Mohammad R. |last4=Aganezov |first4=Sergey S. |last5=Alekseyev |first5=Max A. |display-authors=etal |title=Highly evolvable malaria vectors: The genomes of 16 Anopheles mosquitoes |journal=Science |volume=347 |issue=6217 |date=2015-01-02 |page=43 |pmid=25554792 |pmc=4380271 |doi=10.1126/science.1258522|bibcode=2015Sci...347...43N }}</ref>  The cladogram is based on an analysis of mosquito [[genome]]s by Heafsey and colleagues in 2015:<ref name="Neafsey Waterhouse Abai 2015"/>

{{clade
|label1=[[Diptera]]
|sublabel1= 260 [[myr|mya]]
|1={{clade
   |label1=[[Culicidae]]
   |sublabel1= ''mosquitoes''
   |1={{clade
      |label1='''''Anopheles'''''
      |sublabel1= 100 [[myr|mya]]
      |1={{clade
         |1={{clade
            |label1=subgenus ''[[Anopheles (Cellia)|Cellia]]''
            |1={{clade
               |1={{clade
               |sublabel1= 30 [[myr|mya]]
                  |label1=subgenus ''Pyretophorus''
                  |1={{clade
                     |1=''[[gambiae]]'' complex (Africa)
                     |2=''A. epirotus'' & spp.
                     }}
                  |2=''A. stephensi'' & spp.
                  }}
               |2=''A. dirus'' & spp.
               }}
            |2=subgenus ''Anopheles''
            }}
         |2=subgenus ''[[Anopheles (Nyssorhynchus)|Nyssorhynchus]]'' (Americas)
         }}
      |2=[[Culicinae]]
      }}
   |2=[[Muscomorpha]]
   |sublabel2=''all other flies''
   }}
}}

=== Taxonomy ===

{{main|Taxonomy of Anopheles}}

The genus name ''Anopheles'' was introduced by the German entomologist [[Johann Wilhelm Meigen]] in 1818. He described two species, ''A. birfurcatus'' and the [[type species]], ''[[Anopheles maculipennis]]''. He stated that the name meant {{lang|de|beschwerlich}}, "burdensome".<ref name="Meigen 1818">{{cite book |last=Meigen |first=Johann Wilhelm |author-link=Johann Wilhelm Meigen |date=1818 |title=Systematische Beschreibung der bekannten Europäischen zweiflügeligen Insekten |language=de |trans-title=Systematic description of the known European two-winged insects |location=Aachen |publisher=Friedrich Wilhelm Forstmann |volume=1 |pages=10–12 |url=https://www.biodiversitylibrary.org/item/45833#page/54/mode/1up}}</ref> The name comes from the [[Ancient Greek]] word {{lang|grc|ἀνωφελής}} {{transliteration|grc|anōphelḗs}} 'useless', derived from {{lang|el|ἀν-}} {{transliteration|grc|an-}}, 'not', 'un-' and {{lang|el|[[:wikt:ὄφελος|ὄφελος]]}} {{transliteration|grc|óphelos}} 'profit'.<ref name="Stevenson2010">{{cite book |author=Stevenson, Angus |title=Oxford Dictionary of English |url=https://books.google.com/books?id=anecAQAAQBAJ&pg=PA64 |date=19 August 2010 |publisher=Oxford University Press |isbn=978-0-19-957112-3 |page=64}}</ref>

The taxonomy of the genus was greatly advanced in 1901 when the English entomologist [[Frederick Vincent Theobald]] described 39 ''Anopheles'' species in his 5-volume monograph on the Culicidae.<ref name=Theobald1901>{{cite book |last=Theobald |first=Frederick Vincent |author-link=Frederick Vincent Theobald |date=1901 |title=A Monograph of the Culicidae, or Mosquitoes |location=London |publisher=[[British Museum (Natural History)]] |volume=1 |isbn=978-1-178-51903-7 |pages=115–214 |url=https://archive.org/details/amonographculic03zoolgoog/page/n135/mode/2up}}</ref> He was provided with mosquito specimens sent in to the [[British Museum (Natural History)]] from around the world, on the 1898 instruction of the [[Secretary of State for the Colonies]], [[Joseph Chamberlain]].<ref name="Harbach Kitching 2016"/>

''Anopheles'' (with a nearly worldwide distribution) belongs to the subfamily [[Anophelinae]] alongside two other genera: ''[[Bironella]]'' (restricted to [[Australia]]) and ''[[Chagasia]]'' (restricted to the [[Neotropics]]). The taxonomy remains incompletely settled.<ref name="Krzywinski2003">{{cite journal |last1=Krzywinski |first1=Jaroslaw |last2=Besansky |first2=Nora J. |author-link2=Nora J. Besansky |year=2003 |title=Molecular Systematics of Anopheles: From Subgenera to Subpopulations |journal=Annual Review of Entomology |volume=48 |pages=111–139 |doi=10.1146/annurev.ento.48.091801.112647 |pmid=12208816}}</ref><ref name="Foley 1998">{{cite journal |doi=10.1006/mpev.1997.0457 |pmid=9562985 |title=Evolution and Systematics of ''Anopheles'':Insights from a Molecular Phylogeny of Australasian Mosquitoes |journal=Molecular Phylogenetics and Evolution |volume=9 |issue=2 |pages=262–275 |year=1998 |last1=Foley |first1=Desmond H. |last2=Bryan |first2=Joan H. |last3=Yeates |first3=David |last4=Saul |first4=Allan |bibcode=1998MolPE...9..262F }}</ref> Classification into species is based on morphological characteristics – wing spots, head anatomy, larval and pupal anatomy, chromosome structure, and more recently, on DNA sequences.<ref name="Rattanarithikul 2006">{{cite journal |pmid=17262930 |year=2006 |last1=Rattanarithikul |first1=R. |author-link=Rampa Rattanarithikul|title=Illustrated keys to the mosquitoes of Thailand. IV. Anopheles |journal=The Southeast Asian Journal of Tropical Medicine and Public Health |volume=37 |pages=1–128 |last2=Harrison |first2=B. A. |last3=Harbach |first3=R. E. |last4=Panthusiri |first4=P. |last5=Coleman |first5=R. E. |last6=Panthusiri |first6=P. |issue=Suppl 2 }}</ref><ref name="Walton 2007">{{cite journal |doi=10.1016/j.meegid.2006.05.001 |pmid=16782411 |title=Genetic diversity and molecular identification of mosquito species in the Anopheles maculatus group using the ITS2 region of rDNA |journal=Infection, Genetics and Evolution |volume=7 |issue=1 |pages=93–102 |year=2007 |last1=Walton |first1=C. |last2=Somboon |first2=P. |last3=o'Loughlin |first3=S. M. |last4=Zhang |first4=S. |last5=Harbach |first5=R.E. |last6=Linton |first6=Y.-M. |last7=Chen |first7=B. |last8=Nolan |first8=K. |last9=Duong |first9=S. |last10=Fong |first10=M.-Y |last11=Vythilingum |first11=I. |last12=Mohammed |first12=Z. D. |last13=Trung |first13=Ho Dinh |last14=Butlin |first14=R. K. |bibcode=2007InfGE...7...93W |display-authors=5 }}</ref><ref name="Garros Harbach Manguin 2005">{{cite journal |pmid=16119539 |year=2005 |last1=Garros |first1=C. |last2=Harbach |first2=R. E |last3=Manguin |first3=S. |title=Morphological assessment and molecular phylogenetics of the Funestus and Minimus groups of Anopheles (Cellia) |journal=Journal of Medical Entomology |volume=42 |issue=4 |pages=522–536 |doi=10.1093/jmedent/42.4.522 |s2cid=22776177 |doi-access=free }}</ref> In the taxonomy published by Harbach and Kitching in 2016, it was shown that three species of ''Bironella'' (''[[Bironella confusa|B. confusa]]'', ''[[Bironella gracilis|B. gracilis]],'' and ''[[Bironella hollandi|B. hollandi]]'') are phylogenetically more similar to ''[[Anopheles kyondawensis|A. kyondawensis]]'' than other ''Bironella'' species. That phylogeny argues that, based on genetic similarity, ''[[Anopheles implexus|A. implexus]]'' is divergent from the common ancestor of ''Anopheles''.<ref name="Harbach Kitching 2016">{{cite journal |last1=Harbach |first1=R. E. |last2=Kitching |first2=I. |date=January 2016 |title=The phylogeny of Anophelinae revisited: inferences about the origin and classification of ''Anopheles'' (Diptera: Culicidae) |journal=Zoologica Scripta |volume=45 |pages=34–47 |url=https://nhm.openrepository.com/handle/10141/612216 |doi=10.1111/zsc.12137 |hdl=10141/612216 |s2cid=46364692 |hdl-access=free}}</ref>

== Life cycle ==

Like all mosquitoes, anophelines go through four stages in their life cycles: [[egg (biology)|egg]], [[larva]], [[pupa]], and [[imago|adult]]. The first three stages are aquatic and together last 5–14 days, depending on the species and the ambient temperature. The adult stage is when the female ''Anopheles'' acts as [[malaria]] [[Vector (epidemiology)|vector]]. The adult females can live up to a month (or more in captivity), but most probably do not live more than two weeks in nature.<ref name="cdc">{{citation-attribution|1={{cite web |url=https://www.cdc.gov/malaria/about/biology/mosquitoes/ |title=Anopheles Mosquitoes |publisher=[[Centers for Disease Control and Prevention]] |access-date=December 21, 2016 |date=October 21, 2015}} }}</ref>

=== Eggs ===

[[File:Anopheles egg 2 (cropped).jpg|thumb|upright|''Anopheles'' eggs with their distinctive side floats]]

Adult females lay 50–200 eggs per [[oviposition]]. The eggs are quite small (about {{convert|0.5|mm|in|sigfig=1}} × {{convert|0.2|mm|in|sigfig=1}}). Eggs are laid singly and directly on water. They are unique in that they have floats on either side. Eggs are not resistant to drying and hatch within 2–3 days, although hatching may take up to 2–3 weeks in colder climates.<ref name="cdc"/>

=== Larvae ===

The mosquito larva has a well-developed head with mouth brushes used for feeding, a large [[Thorax (insect anatomy)|thorax]] and a nine-segment [[abdomen]]. It has no legs. In contrast to other mosquitoes, the ''Anopheles'' larva lacks a respiratory siphon, so it positions itself so that its body is parallel to the surface of the water. In contrast, the feeding larva of culicine mosquitoes attach themselves to the water surface with the posterior siphon, the body pointing downwards. Larvae breathe through [[Spiracle (arthropods)|spiracle]]s located on the eighth abdominal segment and so must come to the surface frequently. The larvae spend most of their time feeding on [[algae]], [[bacteria]], and other microorganisms in the thin surface layer. They dive below the surface only when disturbed. Larvae swim either by jerky movements of the entire body or through [[Marine propulsion|propulsion]] with the mouth brushes.<ref name="cdc"/>

Larvae develop through four stages, or [[instar]]s, after which they [[metamorphosis|metamorphose]] into [[pupae]]. At the end of each instar, the larvae molt, shedding their exoskeletons, or skin, to allow for further growth. The larvae occur in a wide range of habitats, but most species prefer clean, unpolluted water. Larvae of ''Anopheles'' have been found in freshwater or saltwater marshes, mangrove swamps, rice fields, grassy ditches, the edges of streams and rivers, and small, temporary rain pools. Many species prefer habitats with vegetation. Others prefer habitats with none. Some breed in open, sun-lit pools, while others are found only in shaded breeding sites in forests. A few species breed in tree holes or the [[leaf axil]]s of some plants.<ref name="cdc"/>

<gallery class=center mode=nolines widths=150 heights=225>
File:AnophelesLarvaPhoto CDCHarryWeinburgh publicdomain.jpg|''Anopheles'' larva
File:Anopheles Culex larvae feeding position-USDA.jpg|Feeding position of an ''Anopheles'' larva (A), culicine larva with its siphon (B)
</gallery>

=== Pupae ===

The pupa (also known as a tumbler) is comma-shaped when viewed from the side. The head and [[Thorax (insect anatomy)|thorax]] are merged into a [[cephalothorax]], with the abdomen curving around underneath it. As with the larvae, the pupa must come to the surface frequently to breathe, which it does through a pair of respiratory trumpets on its cephalothorax. After a few days as a pupa, the dorsal surface of the cephalothorax splits and the adult mosquito emerges.<ref name="cdc"/>

<gallery class=center mode=nolines widths=150 heights=225>
Anopheles (YPM IZ 093745).jpeg|[[Pupa]]
File:The pupa of a mosquito (Anopheles maculipennis). Reproductio Wellcome V0022598 (cropped).jpg|''[[Anopheles maculipennis|A. maculipennis]]'' pupa, breathing at the surface
</gallery>

=== Adults ===

[[File:Anopheles Culex adult resting position-USDA.jpg|thumb|upright=0.5|Resting positions of adult ''Anopheles'' (A, B) are more upright than that of [[Culicinae]] (C).]]

Like all mosquitoes, adult ''Anopheles'' species have slender bodies with three sections: head, thorax and abdomen. The head is specialized for acquiring sensory information and for feeding. It contains the eyes and a pair of long, many-segmented [[Antenna (biology)|antennae]]. The antennae are important for detecting host odours, as well as of breeding sites where females lay eggs.<ref name="cdc"/> Female mosquitoes carrying ''[[Plasmodium]]'' parasites, the causative agents of malaria, are significantly more attracted to human breath and odours than uninfected mosquitoes.<ref name="Smallegange van Gemert van de Vegte-Bolmer Gezan 2013">{{cite journal |last1=Smallegange |first1=Renate C. |last2=van Gemert |first2=Geert-Jan |last3=van de Vegte-Bolmer |first3=Marga |last4=Gezan |first4=Salvador |last5=Takken |first5=Willem |last6=Sauerwein |first6=Robert W. |last7=Logan |first7=James G. |title=Malaria Infected Mosquitoes Express Enhanced Attraction to Human Odor |journal=PLOS ONE |volume=8 |issue=5 |date=2013-05-15 |pmid=23691073 |pmc=3655188 |doi=10.1371/journal.pone.0063602 |article-number=e63602 |bibcode=2013PLoSO...863602S |doi-access=free }}</ref>
The head has an elongated, forward-projecting [[proboscis]] used for feeding, and two [[maxilla|maxillary palps]]. These palps carry the receptors for [[carbon dioxide]], a major attractant that enables the mosquito to locate its host. The [[Thorax (insect anatomy)|thorax]] is specialized for locomotion. Three pairs of legs and a pair of wings are attached to the thorax. The abdomen is specialized for food digestion and egg development. This segmented body part expands considerably when a female takes a blood meal. The blood is digested over time, serving as a source of [[protein]] for the production of eggs, which gradually fill the [[abdomen]].<ref name="cdc"/>

''Anopheles'' can be distinguished from other mosquitoes by the [[palp]]s, which are as long as the proboscis, and by the presence of discrete blocks of black and white scales on the wings. Adults can further be identified by their typical resting position: both sexes rest with their abdomens pointing up, unlike culicine mosquitoes. Adult mosquitoes usually mate within a few days after emerging from the pupal stage. In most species, the males form large [[swarm]]s, usually around dusk, and the females fly into the swarms to mate. The duration from egg to adult varies considerably among species, and is strongly influenced by ambient temperature. Mosquitoes can develop from egg to adult in as little as five days, but it can take 10–14 days in tropical conditions.<ref name="cdc"/>

Males live for about a week, feeding on [[nectar]] and other sources of [[sugar]]. Males cannot feed on blood, as it appears to produce toxic effects and kills them within a few days, around the same lifespan as a water-only diet.<ref>{{cite journal |last1=Nikbakhtzadeh |first1=Mahmood R. |last2=Buss |first2=Garrison K. |last3=Leal |first3=Walter S. |date=2016-01-26 |title=Toxic Effect of Blood Feeding in Male Mosquitoes |journal=Frontiers in Physiology |volume=7 |page=4 |doi=10.3389/fphys.2016.00004 |pmc=4726748 |pmid=26858651 |doi-access=free}}</ref> Females feed on sugar sources for energy, but usually require a blood meal for the development of eggs. After obtaining a full blood meal, the female rests for a few days while the blood is digested and eggs are developed. This process depends on the temperature, but usually takes 2–3 days in tropical conditions. Once the eggs are fully developed, the female lays them and resumes host-seeking. The cycle repeats itself until the female dies. While females can live longer than a month in captivity, most do not live longer than one to two weeks in nature. Their lifespans depend on temperature, humidity, and their ability to successfully obtain a blood meal while avoiding host defenses.<ref name="cdc"/>

<gallery mode=packed heights=350>
File:Anopheles female Turkhud (bw).png|Morphology of female ''Anopheles''
</gallery>

== Ecology ==

=== Distribution ===

''Anopheles'' species live both in tropical areas known for malaria such as sub-Saharan Africa, and in colder latitudes. Malaria outbreaks have in the past occurred in colder climates, for example during the construction of the [[Rideau Canal]] in Canada during the 1820s.<ref name="Wylie 1983">{{cite journal |author=Wylie WNT |s2cid=143040362 |year=1983 |title=Poverty, Distress, and Disease: Labour and the Construction of the Rideau Canal, 1826–32 |journal=[[Labour/Le Travail]] |volume=11 |pages=7–29 |jstor=25140199 |doi=10.2307/25140199}}</ref> ''Anopheles'' species that can transmit malaria are not limited to malaria-endemic areas, so areas where they have been eliminated are constantly at risk of reintroduction of the disease.<ref name="CDC Where Malaria 2020">{{cite web |date=April 9, 2020 |title=CDC - Malaria - About Malaria - Where Malaria occurs |url=https://www.cdc.gov/malaria/about/distribution.html |access-date=December 20, 2022 |website=cdc.gov}}</ref>

[[File:Anopheles-range-map.png|thumb|center|upright=3.5|Global distribution of ''Anopheles'' species covers both the tropics with numerous malarias, and colder areas not subject to malaria at the start of the 21st century.<ref name="CDC Where Malaria 2020"/>]]

=== Habitat ===

''Anopheles'' require bodies of water, possibly small and seasonal,  for their aquatic larvae and pupae. Suitable habitats range from ponds to water tanks, swamps, ditches and puddles.<ref>{{cite web |title=Anopheles Mosquitoes |url=https://globalvectorhub.tghn.org/vector-species/anopheles-mosquitoes/ |website=Global Vector Hub |access-date=15 December 2023}}</ref> The adults can however live in dry regions such as Africa's [[savanna]] and [[Sahel]]. They can travel far from water, and are sometimes blown hundreds of kilometres by suitable winds. Adults can [[aestivate]] for months at a time, becoming dormant in hot dry weather, allowing them to persist through the African [[dry season]].<ref name="Baldini Viana 2023 pp. 1–3">{{cite journal |last1=Baldini |first1=Francesco |last2=Viana |first2=Mafalda |title=Dried out but alive: how mosquitoes survive 8 months |journal=Trends in Parasitology |volume=39 |issue=1 |date=2023 |doi=10.1016/j.pt.2022.11.006 |pages=1–3|pmid=36470782 |doi-access=free }}</ref> Further, ''Anopheles'' have been documented travelling in baggage, such as on aircraft.<ref name="Ibáñez-Justicia Smitz den Hartog van de Vossenberg 2020 p. 3450">{{cite journal |last1=Ibáñez-Justicia |first1=Adolfo |last2=Smitz |first2=Nathalie |last3=den Hartog |first3=Wietse |last4=van de Vossenberg |first4=Bart |last5=De Wolf |first5=Katrien |last6=Deblauwe |first6=Isra |last7=Van Bortel |first7=Wim |last8=Jacobs |first8=Frans |last9=Vaux |first9=Alexander G. C. |last10=Medlock |first10=Jolyon M. |last11=Stroo |first11=Arjan |display-authors=5 |title=Detection of Exotic Mosquito Species (Diptera: Culicidae) at International Airports in Europe |journal=International Journal of Environmental Research and Public Health |volume=17 |issue=10 |date=2020-05-15 |pmid=32429218 |pmc=7277938 |doi=10.3390/ijerph17103450 |page=3450 |doi-access=free }}</ref>

=== Parasites ===

Parasites of ''Anopheles'' include [[Microsporidia]] of the genera ''[[Amblyospora]]'', ''[[Crepidulospora]]'', ''[[Senoma]]'' and ''[[Parathelohania]]''.<ref name="Simakova 2008">{{cite journal |author1=Simakova, A. V. |author2=Pankova, T. F. |year=2008 |title=Ecology and epizootology of microsporidia in malarial mosquitoes (Diptera: Culicidae) from the south of western Siberia |journal=Parazitologiia |volume=42 |issue=2 |pages=139–150 |pmid=18664069 |language=ru}}</ref> Two distinct life cycles are found in the Microsporidia. In the first type, the parasite is transmitted by the oral route and is relatively species nonspecific. In the second, while again the oral route is the usual route of infection, the parasite is ingested within an already infected intermediate host. Infection of the insect larval form is frequently tissue-specific, and commonly involves the [[fat body]]. Vertical (transovarial) transmission also occurs.<ref name="Baker Vossbrinck Becnel 1998">{{cite journal |author1=Baker, Michael D. |author2=Vossbrinck, Charles R. |author3=Becnel, James J. |author4=Andreadis, Theodore G. |year=1998 |title=Phylogeny of ''Amblyospora'' (Microsporida: Amblyosporidae) and related genera based on small subunit ribosomal DNA data: a possible example of host parasite cospeciation |journal=[[Journal of Invertebrate Pathology]] |volume=71 |issue=3 |pages=199–206 |pmid=9538024 |doi=10.1006/jipa.1997.4725 |bibcode=1998JInvP..71..199B |url=http://www.ct.gov/caes/LIB/caes/documents/biographies/BakerJIP98.pdf|archive-url=https://web.archive.org/web/20091106080553/http://ct.gov/caes/LIB/caes/documents/biographies/BakerJIP98.pdf|archive-date=November 6, 2009}}</ref>

The parasitic ''[[Wolbachia]]'' bacteria have been studied for use as control agents.<ref name="Discovery Article">{{cite web |url=http://news.discovery.com/animals/mosquito-parasite-disease-fighting.html |title=Mosquito Parasite Fights Infectious Disease |website=Discovery News |date=1 October 2009 |archive-url=https://web.archive.org/web/20091123222013/http://news.discovery.com/animals/mosquito-parasite-disease-fighting.html |archive-date=23 November 2009 }}</ref>

=== Predators ===

The jumping spider ''[[Evarcha culicivora]]'' indirectly feeds on vertebrate blood by preying on female ''Anopheles''.<ref name="Nelson Jackson Sune 2005">{{cite journal |last1=Nelson |first1=Ximena J. |last2=Jackson |first2=Robert R. |last3=Sune |first3=Godfrey |title=Use of ''Anopheles''-specific prey-capture behavior by the small juveniles of ''Evarcha culicivora'', a mosquito-eating jumping spider |journal=The Journal of Arachnology |volume=33 |issue=2 |pages=541–548 |date=2005 |doi=10.1636/05-3.1 |s2cid=55244513}}</ref> Juvenile spiders choose the ''Anopheles'' over all other prey regardless of whether it actually is carrying blood.<ref name="Jackson Cross 2015">Jackson, Robert R.; Cross, Fiona R. "Mosquito-terminator spiders and the meaning of predatory specialization." The Journal of Arachnology 43.2 (2015): 123–142.</ref> Juvenile spiders have adopted an ''Anopheles''-specific prey-capture behavior, using the posture of ''Anopheles'' as a primary cue to identify them.<ref name="Nelson Jackson Sune 2005"/> ''Anopheles'' has a distinctive resting posture with its abdomen angled up. In this case, the spider approaches from behind the mosquito and under its abdomen, and then attacks from below.<ref name="Nelson Jackson 2006">{{cite journal |last1=Nelson |first1=Ximena J. |last2=Jackson |first2=Robert R. |title=A Predator from East Africa that Chooses Malaria Vectors as Preferred Prey |journal=PLOS ONE |volume=1 |issue=1 |page=132 |date=2006 |doi=10.1371/journal.pone.0000132 |pmid=17205136 |pmc=1762417 |bibcode=2006PLoSO...1..132N |doi-access=free}}</ref>

== Malaria vectors ==

=== Preferred sources for blood meals ===

Since the genus ''Anopheles'' is the sole vector for malaria, it has been studied intensively in the search for effective control methods. One important behavioral factor is the degree to which an ''Anopheles'' species prefers to feed on humans ([[anthropophily]]) or animals such as cattle or birds (zoophily). Anthropophilic ''Anopheles'' are more likely to transmit the malaria parasites from one person to another. Most ''Anopheles'' are not exclusively anthropophilic or zoophilic, including the primary malaria vector in the western United States, [[Anopheles freeborni|''A. freeborni'']].<ref>Carpenter, S. J.; LaCasse, W. J. (1955). ''Mosquitoes of North America (North of Mexico)''. Berkeley, Los Angeles, London: University of California Press. pp. 39–42. {{ISBN|0-520-02638-1}}.</ref><ref>{{cite journal |last=McHugh |first=Chad P. |date=1989-08-01 |title=Ecology of a Semi-Isolated Population of Adult Anopheles Freeborni: Abundance, Trophic Status, Parity, Survivorship, Gonotrophic Cycle Length, and Host Selection |journal=The American Journal of Tropical Medicine and Hygiene |volume=41 |issue=2 |pages=169–176 |doi=10.4269/ajtmh.1989.41.169 |pmid=2774063}}</ref> However, the primary malaria vectors in [[Africa]], ''[[Anopheles gambiae|A. gambiae]]'' and ''A. funestus'', are strongly anthropophilic and are consequently major vectors of human malaria.<ref name="cdc"/>

=== Probability of transmitting malaria ===

Once ingested by a mosquito, malaria parasites must undergo development within the mosquito before they are infectious to humans. The time required for the parasite to develop in the mosquito (the extrinsic [[incubation period]]) ranges from 10 to 21 days, depending on the parasite species and the temperature. If a mosquito does not survive long enough for the parasite to develop, then she transmits no parasites.<ref name="cdc"/>

It is not possible to measure directly the lifespans of mosquitoes in nature, but indirect estimates of daily survivorship have been made for several ''Anopheles'' species. Estimates of daily survivorship in [[Tanzania]] of ''A. gambiae'', the vector of the dangerous ''[[Plasmodium falciparum]]'' parasite, ranged from 0.77 to 0.84, meaning that after one day, between 77% and 84% have survived.<ref name="Charlwood Smith Billingsley Takken 1997">{{cite journal |last1=Charlwood |first1=J. D. |last2=Smith |first2=T. |last3=Billingsley |first3=P. F. |last4=Takken |first4=W. |last5=Lyimo |first5=E. O. K. |last6=Meuwissen |first6=J. H. E. T. |title=Survival and infection probabilities of anthropophagic anophelines from an area of high prevalence of Plasmodium falciparum in humans |journal=Bulletin of Entomological Research |volume=87 |issue=5 |date=1997 |doi=10.1017/S0007485300041304 |pages=445–453 |url=http://doc.rero.ch/record/298415/files/S0007485300041304.pdf }}</ref> Assuming this survivorship is constant through the adult life of a mosquito, less than 10% of female ''A. gambiae'' would survive longer than a 14-day extrinsic incubation period. If daily survivorship increased to 0.9, over 20% of mosquitoes would survive longer than the same period. Control measures that rely on [[insecticide]]s (e.g. [[indoor residual spraying]]) may actually impact malaria [[Transmission (medicine)|transmission]] more through their effect on adult longevity than through their effect on the population of adult mosquitoes.<ref name="cdc"/>

=== Patterns of feeding and resting ===

Most ''Anopheles'' are [[crepuscular]] (active at dusk or dawn) or [[nocturnal]] (active at night). Some feed indoors (endophagic), while others feed outdoors (exophagic). After feeding, some blood mosquitoes prefer to rest indoors (endophilic), while others prefer to rest outdoors (exophilic). Biting by nocturnal, endophagic ''Anopheles'' can be markedly reduced through the use of [[insecticide]]-treated bed nets or through improved housing construction to prevent mosquito entry (e.g. [[window screen]]s). Endophilic mosquitoes are readily controlled by indoor spraying of residual insecticides. In contrast, exophagic/exophilic vectors are best controlled by destroying breeding sites, such as by filling in ponds.<ref name="cdc"/>

=== Gut flora ===

Because transmission of disease by the mosquito requires ingestion of blood, the gut flora may have a bearing on the success of infection of the mosquito host. The larval and pupal gut is largely colonized by photosynthetic [[cyanobacteria]], while in the adult, [[gram-negative bacteria]] in the [[Pseudomonadota]] and [[Bacteroidota]] phyla predominate. Blood meals drastically reduce the diversity of microorganisms in the gut, favouring bacteria.<ref name="Wang 2011">{{cite journal |title=Dynamic gut microbiome across life history of the malaria mosquito Anopheles gambiae in Kenya |doi=10.1371/journal.pone.0024767 |vauthors=Wang Y, ((Gilbreath TM III)), Kukutla P, Yan G, Xu J |year=2011 |editor1-last=Leulier |editor1-first=François |journal=PLOS ONE |volume=6 |issue=9 |article-number=e24767 |pmid=21957459 |pmc=3177825 |bibcode=2011PLoSO...624767W |doi-access=free}}</ref>

== Control ==
[[File:PMI IRS2-2-1140x684.jpg|alt=Person wearing personal protective equipment performing indoor residual spraying on a house to prevent mosquitoes.|thumb|Person wearing personal protective equipment performing indoor residual spraying on a house to prevent malaria.]]

=== Insecticide control and resistance ===

[[Insecticide]]s have offered a first line of approach to ridding areas of malarial mosquitoes. However, mosquitoes, with a short generation time, may rapidly evolve resistance, as experienced during the Global Malaria Eradication Campaign of the 1950s.<ref name="Najera 1999">{{cite web |last1=Najera |first1=J. A. |title=Malaria Control: Achievements, Problems, & Strategies |url=https://iris.who.int/bitstream/handle/10665/66640/WHO_MAL_99.1087.pdf?sequence=1 |publisher=[[World Health Organization]] |access-date=23 January 2024 |ref=WHO/MAL/99.1087 |date=1999}}</ref> The use of insecticides in agriculture has resulted in resistance in mosquito populations, implying that an effective control program must monitor for resistance and switch to other means if resistance is detected.<ref name="CDC Biology">{{cite web |title=Biology: Anopheles Mosquitoes (tab 5) |date=16 July 2020 |url=https://www.cdc.gov/malaria/about/biology/#tabs-1-5 |publisher=[[Centers for Disease Control and Prevention]] |access-date=16 December 2023}}</ref>

=== Eradication ===

In 2016, a CRISPR-Cas9 [[gene drive]] system was proposed to eradicate ''Anopheles gambiae'',<ref>{{cite journal |last1=Hammond |first1=Andrew |last2=Galizi |first2=Roberto |last3=Kyrou |first3=Kyros |last4=Simoni |first4=Alekos |last5=Siniscalchi |first5=Carla |last6=Katsanos |first6=Dimitris |last7=Gribble |first7=Matthew |last8=Baker |first8=Dean |last9=Marois |first9=Eric |last10=Russell |first10=Steven |last11=Burt |first11=Austin |display-authors=5 |date=January 2016 |title=A CRISPR-Cas9 gene drive system targeting female reproduction in the malaria mosquito vector Anopheles gambiae |journal=Nature Biotechnology |volume=34 |issue=1 |pages=78–83 |doi=10.1038/nbt.3439 |pmid=26641531 |pmc=4913862}}</ref> by deleting the ''[[Doublesex|dsx]]'' gene, causing female sterility. Such a gene drive system has been shown to suppress an entire caged ''A. gambiae'' population<ref>{{cite journal |last1=Kyrou |first1=Kyros |last2=Hammond |first2=Andrew M. |last3=Galizi |first3=Roberto |last4=Kranjc |first4=Nace |last5=Burt |first5=Austin |last6=Beaghton |first6=Andrea K. |last7=Nolan |first7=Tony |last8=Crisanti |first8=Andrea |date=November 2018 |title=A CRISPR–Cas9 gene drive targeting doublesex causes complete population suppression in caged Anopheles gambiae mosquitoes |journal=Nature Biotechnology |volume=36 |issue=11 |pages=1062–1066 |doi=10.1038/nbt.4245 |pmid=30247490 |pmc=6871539 |doi-access=free}}</ref> within 7–11 generations, typically less than a year. This has raised concerns with both the efficiency of a gene drive system as well as the ethical and ecological impact of such an eradication program.<ref>{{cite journal |last1=Taning |first1=Clauvis Nji Tizi |last2=Van Eynde |first2=Benigna |last3=Yu |first3=Na |last4=Ma |first4=Sanyuan |last5=Smagghe |first5=Guy |date=April 2017 |title=CRISPR/Cas9 in insects: Applications, best practices and biosafety concerns |journal=Journal of Insect Physiology |volume=98 |pages=245–257 |doi=10.1016/j.jinsphys.2017.01.007 |pmid=28108316|bibcode=2017JInsP..98..245T |url=https://biblio.ugent.be/publication/8511395/file/8511396 |url-access=subscription }}</ref> Therefore, there have been efforts to use the gene drive system to more efficiently introduce genes of ''Plasmodium'' resistance into the species, such as targeting and knocking out the ''FREP1'' gene in ''Anopheles gambiae.''<ref>{{cite journal |last1=Dong |first1=Yuemei |last2=Simões |first2=Maria L. |last3=Marois |first3=Eric |last4=Dimopoulos |first4=George |date=2018-03-08 |title=CRISPR/Cas9 -mediated gene knockout of Anopheles gambiae FREP1 suppresses malaria parasite infection |journal=PLOS Pathogens |volume=14 |issue=3 |article-number=e1006898 |doi=10.1371/journal.ppat.1006898 |pmid=29518156 |pmc=5843335 |doi-access=free }}</ref> Researchers in [[Burkina Faso]] have created a strain of the fungus ''[[Metarhizium pinghaense]]'' that is genetically engineered to produce the venom of an Australian [[funnel-web spider]]; exposure to the fungus caused populations of ''Anopheles'' to crash by 99% in a controlled trial.<ref>{{cite news |last=Gallagher |first=James |date=31 May 2019 |title=GM fungus rapidly kills 99% of malaria mosquitoes, study suggests |url=https://www.bbc.com/news/health-48464510 |work=[[BBC News Online]] |access-date=31 Dec 2019}}</ref>

== See also ==

* [[Tropical disease]]

==References ==

{{reflist|30em}}

==External links==

{{Commons category|Anopheles}}

* [https://web.archive.org/web/20040320182058/http://www.anobase.org/ ''Anopheles'' Database] (archived)
* [https://www.vectorbase.org/Anopheles_gambiae/Info/Index ''Anopheles gambiae'' Genome and Related Data] {{Webarchive|url=https://web.archive.org/web/20121203201743/https://www.vectorbase.org/Anopheles_gambiae/Info/Index |date=2012-12-03 }}
* [https://www.cdc.gov/Malaria/ CDC – National Center for Infectious Diseases, Division of Parasitic Diseases; Malaria]
* [https://web.archive.org/web/20060921000929/http://www.cdc.gov/malaria/biology/mosquito/map.htm CDC – World map showing distribution of various ''Anopheles'' species] (archived)
* [http://www.wrbu.org/  Walter Reed Biosystematics Unit.] ({{Webarchive|url=https://web.archive.org/web/20181215173327/https://www.wrbu.org/|date=15 December 2018|title=Archived version}}) – Links to the online mosquito catalog, keys for mosquito identification, images and information on medically important species and much more.
* [https://web.archive.org/web/20150330171641/http://www.map.ox.ac.uk/ Malaria Atlas Project] (archived)
* [https://web.archive.org/web/20180509035207/http://www.metapathogen.com/mosquito/anopheles/ ''Anopheles gambiae'' taxonomy, facts and life cycle] (archived)
* [https://web.archive.org/web/20170130141158/http://entomology.ifas.ufl.edu/creatures/aquatic/Anopheles_quadrimaculatus.htm ''Anopheles quadrimaculatus'', common malaria mosquito] (archived) on the [[University of Florida]] / [[Institute of Food and Agricultural Sciences]] ''Featured Creatures'' website
*[http://animaldiversity.ummz.umich.edu/site/accounts/classification/Anopheles.html ''Anopheles''] {{Webarchive|url=https://web.archive.org/web/20230821202050/https://animaldiversity.org/site/accounts/classification/Anopheles.html|date=5 May 2021|title=Archived version}}

{{malaria}}
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[[Category:Anopheles| ]]
[[Category:Mosquito genera]]
[[Category:Insect vectors of human pathogens]]
[[Category:Malaria]]
[[Category:Taxa named by Johann Wilhelm Meigen]]