Subgenus Polyleptiomyia Theobald, 1905
Aedes albocephalus (Theobald, 1903), original combination: Stegomyia albocephala.
Subfamily Culicinae, tribe Aedini, genus Aedes. Subgenus Polyleptiomyia includes only two species. Subgenus abbreviation – Pmt.
The known species of subgenus Polyleptiomyia exhibit the following distinctive features. Characters that diagnose the subgenus (as genus Polyleptiomyia) in the phylogenetic analyses of Reinert et al. (2009), based on Ae. albocephalus, are indicated by an asterisk (*).
ADULTS – Vertex of head mainly with narrow decumbent scales (almost entirely broad in males of Ae. albocephalus); erect scales on vertex and occiput; maxillary palpus and proboscis entirely dark-scaled, maxillary palpus of males slightly longer than proboscis; scutum with variable mixture of dark and pale scales; paratergite with narrow scales; scutellum with narrow scales on midlobe, sometimes also with some broad scales, lateral lobes with broad or mixture of broad and narrow scales; *lower proepisternal scales present; postspiracular scales present or absent; subspiracular scales present; prealar scales absent; wing dark-scaled with a line of pale scales at base of costa; femora each with very small inconspicuous pale knee spot (absent on fore- and midfemora of males?); hindtibia with small apical pale spot; tarsi dark-scaled (tarsomere 1 sometimes pale-scaled posteriorly in Ae. albocephalus); fore- and midungues equal, both pair with 1 tooth, fore- and *midungues of males unequal, larger unguis with 1 tooth, smaller unguis simple, hindungues equal and simple in both sexes; abdominal terga with basolateral pale patches, with or without narrow pale basomesal bands or spots (always absent in males?), sterna pale-scaled with narrow apical dark bands. FEMALE GENITALIA – Tergum VIII and sternum VIII without scales, basolateral areas of tergum expanded outward, caudal margin straight, sternum VIII wider than long, *caudal margin with median emargination; cercus widest in proximal 0.5, scales absent; postgenital lobe with median caudal emargination; insula tongue-like, setae or tuberculi present. MALE GENITALIA – Gonocoxite elongate, with setose basal mesal lobe; gonostylus forked near mid-length, dorsal arm with fine apical seta, ventral arm bearing a strong terminal gonostylar claw, no other setae present (*setae absent on distal 0.33 of gonostylus); aedeagus elongate, comprised of 2 lateral plates, each with few apical teeth; paraproct long, tapered to point; cereal setae absent. LARVAE – Antenna slender, curved, with few spicules; seta 1-A multi-branched; *seta 1-C spiniform; comb comprised of relatively few spine-like scales in patch; siphon relatively short, pecten extending to about mid-length of siphon, seta 1-S inserted well beyond distal pecten spine; saddle incomplete; seta 1-X single, about as long as saddle; ventral brush (seta 4-X) with 3–5 precratal setae and about 5 pairs of setae on grid with lateral and transverse bars. PUPAE – Poorly known; trumpet with weakly developed tracheoid area; seta 9-VIII inserted on corner of segment, with 4 or more branches; paddle oval, rounded posteriorly, without fringe of hair-like spicules, midrib well developed; seta 1-Pa single or forked; seta 2-Pa absent. See Aedes.
The evolutionary relationships of subgenus Polyleptiomyia are uncertain. Aedes albocephalus was recovered in a basal relationship to subgenera Bifidistylus + (Albuginosus + (Tewarius + (Christophersiomyia + (Huaedes + Leptosomatomyia)))) in the morphology-based phylogenetic study of Aedini conducted by Reinert et al. (2009). Polyleptiomyia was not associated with other generic-level taxa in the phylogeny of Wilkerson et al. (2015).
Hopkins (1952) reported that the immature stages of Ae. albocephalus typically inhabit grassy swamps, but are also found in ground pools of various kinds, marshy pools in small streams and drains, and crab holes; exceptionally found in tins and tree hole (van Someren et al., 1955). Larvae of this species have been found in saltwater marshes and tidal pools in South Africa (Muspratt, 1951; McIntosh, 1975), confirming Hopkins supposition that “it can tolerate some degree of salinity”. Females readily feed on domestic mammals and sometimes also on humans, but they rarely enter human dwellings (Muspratt, 1951; van Someren et al., 1955; McIntosh, 1975). Nothing has been reported about the biology Ae. gandarai.
Worth et al. (1961) reported the isolation of Middelburg virus from Ae. albocephalus in South Africa, but species of subgenus Polyleptiomyia are not considered to be of medical importance.
Sub-Saharan Africa: Country records for Ae. albocephalus include Angola, Benin, Cameroon, Gambia, Glorioso Islands, Juan de Nova Island, Kenya, Liberia, Madagascar, Mozambique, Mayotte, Nigeria, Senegal, Seychelles, South Africa, Togo, Uganda and Zimbabwe; Ae. gandarai is only known from Príncipe and São Tomé.
Reinert et al., 2009 (as genus, morphology, phylogeny); Reinert, 2010 (as genus, female genitalia); Wilkerson et al., 2015 (phylogeny, classification).
albocephalus (Theobald, 1903) gandarai da Cunha Ramos, Capela & Ribeiro, 1995