Aedes simpsoni (Theobald, 1905), original combination: Stegomyia simpsoni.
Subfamily Culicinae, tribe Aedini, genus Aedes, subgenus Stegomyia. The Simpsoni Group includes the 10 species.
ADULTS – The adults of the Simpsoni Group are diagnosed and distinguished from other species of subgenus Stegomyia by the following combinations of characters. The characters that diagnose the Simpsoni Group (as subgenus Mukwaya) in the phylogenetic study of Reinert et al. (2009) are indicated with an asterisk (*). ADULTS – Maxillary palpus with white scales; scutum with distinct patch of pale falcate scales on scutal fossa and a pair of submedian pale stripes; *anterior supraalar-posterior antealar area without transverse patch of pale scales; dorsocentral setae present; prescutellar area without broad metallic silvery scales; paratergite with broad pale scales; *upper proepisternum with 5–19 setae; postspiracular area without scales; subspiracular area with broad pale scales; forefemur without knee-spot, present on mid- and hindfemora; midfemur with large, pale spot on anterior surface; foretibia with basal pale band; hindtibia dark anteriorly, with or without pale stripe in basal area; hindtarsus with a basal pale band at least on tarsomeres 1‒3; hindtarsomere 4 all dark, all pale or with basal pale band. FEMALE GENITALIA – Tergum VIII with scales on distal 0.7–0.8, setae on distal 0.2‒0.7, VIII-Te index 0.6–0.9; posterior margin of sternum VIII with broadly rounded posterolateral lobe on either side of shallow median emargination, scales on distal 0.6‒0.9, VIII-S index 0.6–1.0; tergum IX with deep median posterior emargination, IX-Te index 0.7–1.4; postgenital lobe with 7–10 setae on each side of midline; cercus rounded apically, broad scales on distal 0.7–0.9, cercus index 2.2–2.7. MALE GENITALIA – Posterior margin of tergum IX with slightly separated lateral lobes; gonostylar claw very short, about 0.13 length of gonostylus; aedeagus with short teeth only; aedeagus with short teeth only; paraproct with sternal arm. LARVAE and PUPAE – It is not possible to provide a complete diagnosis of the larval and pupal stages at this time. Characters that diagnose the Mukwaya clade in study of Reinert et al. (2009) are as follow. LARVAE – Seta 5-C 0.21–0.38 median length of dorsal apotome; seta 4-M branched; seta 3-I branched; seta 1a-S within pecten; seta 3-X single. PUPAE ‒ Seta 3-VI inserted mesal or directly anterior to seta 1-VI. See subgenus Stegomyia.
The Simpsoni Group was recovered as sister to Ae. poweri in the cladistic analyses of Reinert et al. (2009) based on extensive morphological data of tribe Aedini. However, St. poweri is the nominotypical species of the Power Group and a relationship with this species requires further investigation. The Simpsoni Group (as subgenus Mukwaya) + Ae. poweri was recovered as sister to Ae. aegypti (as subgenus Stegomyia) + Ae. apicoargenteus. Aedes apicoargenteus, nominotypical species of the Apicoargenteus Group, differs markedly from Ae. aegypti, which with Ae. pia and Ae. mascarensis, are the only species of the the Aegypti Group. Three species of the group, Ae. bromeliae, Ae. lilii and Ae. simpsoni, were recovered as a strongly supported monophyletic clade in the maximum likelihood phylogeny of Soghigian et al. (2017) based on molecular markers.
Females of Ae. bromeliae, gandaensis, simpsoni, strelitziae, subargenteus and woodi, are known to bite humans.
Aedes bromeliae is an important vector of yellow fever virus in East Africa. It was incriminated in the vector of yellow fever virus in Uganda (Mahaffy et al., 1942; Smithburn & Haddow, 1946). Aedes strelitziae in South Africa has been shown to transmit yellow fever virus from one Rhesus monkey to another under laboratory conditions (Gillett & Ross, 1953). Other viruses have been isolated from wild-caught Ae. bromeliae (misidentified as Ae. simpsoni, see Huang, 1979, 1986).
Species of the Simpsoni Group are recorded from the following countries of sub-Saharan Africa: Angola, Benin, Burkina Faso, Cameroon, Central African Republic, Comoros, Congo, Cote d'Ivoire, Democratic Republic of the Congo, Ethiopia, Ghana, Guinea, Kenya, Liberia, Malawi, Mozambique, Nigeria, Senegal, Sierra Leone, South Africa, Sudan, Swaziland, Tanzania, Uganda and Zimbabwe.
Pajot, 1975, 1976a, 1976b, 1976c, 1977 (type species, taxonomy, bionomics); Huang, 1979, 1986 (as simpsoni complex, taxonomy); Reinert, 2000 (as Simpsoni Assemblage, female genitalia); Huang, 2004 (as Simpsoni Subgroup, taxonomy, adult keys). As Stegomyia (Mukwaya): Reinert et al., 2009 (as subgenus Mukwaya of genus Stegomyia, morphology, phylogeny). Older literature: Edwards (1941) included descriptive information and some illustrations for Ae. kivuensis, Ae. simpsoni, Ae. subargenteus and Ae. woodi; Hopkins (1952) described the fourth-instar larvae of Ae. simpsoni, Ae. strelitziae and Ae. subargenteus. Mattingly (1952, 1953) and Muspratt (1956) provided information on the taxonomy and distribution for most species of the group; Soghigian et al., 2017 (phylogenetic relationships).