Culex quinquefasciatus

Culex quinquefasciatus
Left: male, right: female
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Diptera
Family:	Culicidae
Genus:	Culex
Species:	C. quinquefasciatus
Binomial name
Culex quinquefasciatus Say, 1823
Synonyms
Culex acer Walker, 1848 Culex aestuans Wiedemann, 1828 Culex aikenii Dyar & Knab, 1908 Culex albolineatus Giles, 1901 Culex anxifer Bigot, 1859 Culex aseyehae Dyar & Knab, 1915 Culex autumnalis Weyenbergh, 1882 Culex barbarus Dyar & Knab, 1906 Culex cartroni Ventrillon, 1905 Culex christophersii Theobald, 1907 Culex cingulatus Doleschall, 1856 Culex cubensis Bigot, 1857 Culex didieri Neveu-Lemaire, 1906 Culex fatigans Wiedemann, 1828 Culex fouchowensis Theobald, 1901 Culex hensemaeon Dyar, 1920 Culex luteoannulatus Theobald, 1901 Culex macleayi Skuse, 1889 Culex minor Theobald, 1908 Culex nigrirostris Enderlein, 1920 Culex pallidocephala Theobald, 1904 Culex penafieli Sanchez, 1885 Culex pungens Wiedemann, 1828 Culex pygmaeus Neveu-Lemaire, 1906 Culex quasilinealis Theobald, 1907 Culex quasipipiens Theobald, 1901 Culex raymondii Tamayo, 1907 Culex reesi Theobald, 1901 Culex revocator Dyar & Knab, 1909 Culex sericeus Theobald, 1901 Culex serotinus Philippi, 1865 Culex skusii Giles, 1900 Culex trillineatus Theobald, 1901 Culex zeltneri Neveu-Lemaire, 1906 Culicelsa fuscus Taylor, 1914

Culex quinquefasciatus Say, 1823 (originally named Culex fatigans), commonly known as the southern house mosquito, is a medium-sized mosquito found in tropical and subtropical regions of the world. It is the vector of Wuchereria bancrofti, avian malaria, and arboviruses including St. Louis encephalitis virus, Western equine encephalitis virus, zika virus^[1] and West Nile virus.^[2] It is taxonomically regarded as a member of the Culex pipiens species complex.^[3] Its genome was sequenced in 2010, and was shown to have 18,883 protein-coding genes.^[4]

Description

Adult C. quinquefasciatus is a medium-sized mosquito and is brown in colour. The body is about 3.96 to 4.25 mm long. While the main body is brown, the proboscis, thorax, wings, and tarsi are darker than the rest of the body. The head is light brown with the lightest portion in the center. The antennae and the proboscis are about the same length, but in some cases, the antennae are slightly shorter than the proboscis. The flagellum has 13 segments that may have few or no scales. The scales of the thorax are narrow and curved. The abdomen has pale, narrow, rounded bands on the basal side of each tergite. Males can be differentiated from females in having large palps and feathery antennae.^[5]

The larva has a short and stout head. The mouth brushes have long yellow filaments used for filtering organic materials. The abdomen consists of eight segments, the siphon, and the saddle. Each segment has a unique setae pattern. The siphon is on the dorsal side of the abdomen, and is four times longer than its breadth. The siphon has multiple setae tufts. The saddle is barrel-shaped and located on the ventral side of the abdomen with four long anal papillae protruding from the posterior end.^[2]

Lifecycle

Mature C. quinquefasciatus females fly at night to nutrient-rich standing water to lay eggs. The larvae feed on organic material in the water and require between five and eight days to complete their development at 30 °C. The larvae pass through four larval instars, and towards the end of the fourth instar, they stop eating and undergo moulting to give rise to pupae. After 36 hours at 27 °C, adults emerge. The exact timing of development can vary depending on temperature. Both males and females take sugar meals from plants. But after mating, the female seeks a blood meal on mammals and birds. Ingested blood is necessary for egg development. A single female can lay up to five rafts of eggs in a lifetime, with each raft containing thousands of eggs. The exact number varies depending on climatic conditions.^[2]

As a vector

The southern house mosquito can transmit zoonotic diseases that affect humans and wild and domestic animals, such as lymphatic filariasis, avian malaria, St. Louis encephalitis, Western equine encephalitis, and West Nile fever, and may be a vector of the Zika virus.^[6] It causes infection through biting during blood meal. In the southern U.S., it is the primary vector of St. Louis encephalitis virus. In India and Southeast Asia, it is the primary vector of Wuchereria bancrofti, a nematode that causes lymphatic filariasis. It acts as an intermediate host for the helminth parasite by harbouring the larval stages.^[7] It also transmits Plasmodium relictum, a malarial parasite of birds, and is the principal vector in Hawaii. It is the definitive host for malarial parasite as it harbours the sexual cycle.^[8]

Bionomics

It breeds profusely in dirty water collections, including stagnant drains, cesspools, septic tanks with leaks, burrow pits, and almost all organic polluted water collections. In optimum temperature and humidity, the lifecycle will be completed in seven days, passing through the egg, larval, pupal, and adult stages.

The C. quinquefasciatus shows a preference to feed on the blood of birds but will also commonly bite humans. It rests in trees and high places.^[9]

References

External links

• "Culex quinquefasciatus". VectorBase. 
• Disease monger
• Identification guide at University of Florida
• NSW Arbovirus Surveillance & Vector Monitoring Program
• Taxonomy at UniProt