Revision of Subgenus Stegomyia Theobald, 1901 from Thu, 2020-08-27 15:35

Type species: 

Aedes aegypti (Linnaeus, 1762), original combination: Culex aegypti.

Classification: 

Subfamily Culicinae, tribe Aedini, genus Aedes. Subgenus Stegomyia is a large genus with 128 species classified in six species groups (group uncertain for one species), two groups of which are further divided into subgroups. Subgenus abbreviation – Stg.

Characteristics: 

Stegomyia is characterized and distinguished from other generic-level taxa of subfamily Culicinae by the following combinations of characters. Characters that diagnose the type species in the phylogenetic study of Reinert et al. (2009) are indicated with an asterisk (*). ADULTS ‒ Onate mosquitoes, usually dark with white or silver markings; vertex of head with broad decumbent scales, erect scales restricted to occiput, usually few in number; clypeus bare or with scales; *lateral surface of antennal pedicel with scales; proboscis usually about as long as forefemur; maxillary palpi with white scales; maxillary palpus of females about 0.15–0.30 length of proboscis, comprised of 3 or 4 palpomeres, palpomere 4 minute when present; maxillary palpus of males longer than 0.5 length of proboscis, comprised of 5 palpomeres, palpomeres 4 and 5 subequal, slender, *up-turned, with few setae, their combined length at least 0.4 combined length of proximal palpomeres; scutum entirely or mainly covered with narrow scales; acrostichal setae absent; scutellum usually with broad decumbent scales; paratergite usually with scales; mesopostnotum bare; antepronotum usually with broad decumbent scales; *lower proepisternal scales present; prespiracular setae absent; postspiracular setae present; lower mesepimeral setae usually absent; postprocoxal membrane without scales; wing with narrow plume scales, *some pale scales near base of costa; hindtarsus with basal white band on one or more tarsomeres; ungues of fore- and midlegs toothed or simple, those of hindleg usually simple, anterior fore- and midungues of males larger than posterior ungues; laterotergite of abdominal segment I with scales. FEMALE GENITALIA ‒ Segment VIII retractile, somewhat compressed, sternum VIII with prominent rounded lateral lobes; segment IX with wide and deep posterior emargination, shorter than cercus; cercus broad and rather short, with scales; postgenital lobe with shallow caudal emargination; insula tongue-like, longer than broad, with minute setae and 2–10 larger setae on apical 0.25–0.50; cerci short and broad; 3 spermathecae, one larger than the other 2. MALE GENITALIA ‒ *Sternum IX bare; gonocoxite sometimes with membranous mesal area, gonostylus usually simple, gonostylar claw present, inserted apically or subapically, *developed as relatively narrow spiniform, *truncate, rarely slightly rounded; claspette well developed, with numerous setae; aedeagus strongly toothed; aedeagus comprised of distinct lateral plates, each with numerous teeth; paraproct without teeth; cercal setae absent. LARVAE ‒ Antenna without spicules; setae 4–6-C far forward, inserted cephalad of antennal base; seta 4-C well developed, branched; setae 5,6-C seldom strongly branched; seta 4-C closer to seta 6-C than to seta 5-C, cephalad and mesad of seta 6-C; seta 6-C cephalad of setae 5-C and 7-C; seta 6-M branched; *seta 7-C inserted at approximately same level as seta 5-C; *seta 4-P branched; *seta 5-P longer that seta 6-P; seta 12-I not developed; seta 2-VIII distant from seta 1-VIII; comb scales usually in single row; saddle complete or incomplete; *seta 2-X single or double, rarely triple; ventral brush (seta 4-X) with 4 or 5 pairs of setae on grid or boss, without precratal tufts. PUPAE ‒ Subgeneric characters not evident; seta 8-C well posterior to trumpet, at least halfway between trumpet and mesonotum. See Aedini.

Phylogenetic relationships: 

Stegomyia, as defined by Reinert et al. (2009), appears to be a highly evolved monophyletic group with uncertain affinities. The Stegomyia was recovered as sister to a clade comprised of 10 aedine genera in the phylogeny of Reinert et al. based on extensive morphological data, including Alanstonea, Belkinius, Cornetius, Diceromyia, Eretmapodites, Heizmannia, Lorrainea, Patmarksia, Udaya and Zeugnomyia. Huang (1979, 2004) suggested that Stegomyia exhibits “strongest affinities” with Diceromyia based on “important” shared characters of the adult and immature stages. In the phylogeny of Wilkerson et al. (2015), Stegomyia was recovered as the sister of subgenus Cornetius within a large polytomy that included 11 other subgenera and the genera Heizmannia, Udaya and Zeugnomyia. Stegomyia, represented by 33 species, was recovered as a monophyletic group in the maximum likelihood phylogeny of Soghigian et al. (2017) based on molecular markers. Their findings support the monophyly of the Aegypti and Simpsoni Groups.

Bionomics and disease relations: 

The immature stages of species of subgenus Stegomyia are found in natural and artificial containers. Typical habitats are tree holes, but many species inhabit small amounts of water contained in dead and fallen plant parts. A few species utilise rock holes, crab holes and the leaf axils of various plants. Eggs are normally resistant to desiccation and hatch when the habitat is filled with water. Females are typically diurnal and many species (approximately 50) are known to bite humans. They also feed on a variety of domestic and wild animals, including mammals, birds, reptiles and amphibians. 

Subgenus Stegomyia is a medically important group. Aedes aegypti is the classical vector of yellow fever and dengue fever viruses and a proven vector of other viruses. Aedes albopictus is also an important vector of dengue fever virus. Other recognised vectors of yellow fever virus include Ae. africanus and Ae. luteocephalus in areas of central and western Africa and Ae. bromeliae in East Africa. Some species of the Scutellaris Group are efficient vectors of Wuchereria bancrofti in the South Pacific. Various arboviruses have been isolated from other species of the subgenus.

Distribution: 

Species of subgenus Stegomyia have distributions in the Afrotropical, Australasian and Oriental Regions. Two species, Ae. aegypti and Ae. albopictus, have been transported to areas of the Nearctic, Neotropical and Palaearctic Regions by human agency.

Principal references: 

Belkin, 1962 (South Pacific); Huang, 1977, 1979 (Oriental Region); Lee et al., 1987 (Australia); Huang, 1990 (Africanus Group, Afrotropical Region);Reinert, 2000 (female genitalia);  Huang, 2004 (Afrotropical Region); Reinert et al., 2004, 2006, 2008, 2009 (as genus, morphology, phylogeny); Rattanarithikul et al., 2010 (as genus, Thailand, keys, bionomics); Wilkerson et al., 2015 (phylogeny, classification); Wilkerson et al., 2015 (phylogeny, classification); Soghigian et al., 2017 (phylogenetic relationships).

Nomina dubia

ciliaris (Linnaeus, 1767)
niveus (Eichwald, 1837)
rimandoi Basio, 1971

Species groups: 

Aegypti Group (see).
Africanus Group (see).
Apicoargenteus Group (see).
Dendrophilus Group (see).
Edwardsi Group (see).
Grantii Group (see).
Maehleri Group (see).
Metallicus Group (see).
Pandani Group (see).
Poweri Group (see).
Pseudonigeria Group (see).
Scutellaris Group (see).
Simpsoni Group (see).
Unilineatus Group (see).
W-albus Group (see).
Zoromorphus Group (see).

Species - Group uncertain: 

vinsoni Mattingly, 1953

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith