Subgenus Halaedes Belkin, 1962
Aedes australis (Erichson, 1842), original combination: Culex australis.
Subfamily Culicinae, tribe Aedini, genus Aedes. Subgenus Halaedes includes three species. Subgenus abbreviation – Hal.
Species of subgenus Halaedes are unornamented mosquitoes with dark tarsi, long setae on the antennal pedicel, numerous postspiracular and prealar setae, and prominent patches of broad scaling on the postspiracular area, prealar area, mesokatepisternum and mesepimeron; characters that define the Halaedes clade in the phylogenetic analysis of Reinert et al. (2009) are indicated by an asterisk (*) in the following description.
ADULTS – Eyes distinctly separated above antennae; decumbent scales of vertex mainly narrow; erect scales numerous, seta-like in front; maxillary palpus of females about 0.2 length of proboscis, with 5 palpomeres, palpomere 5 small; maxillary palpus of males slightly shorter than proboscis, palpomeres 4 and 5 long, widened, setae numerous from middle of palpomere 3; antenna shorter than proboscis; scutal scales narrow; acrostichal setae and dorsocentral setae present; scutellum with narrow scales; paratergite with scales; pleural scaling extensive, scales broad, *mesokatepisternal scales in one large patch; pleural setae numerous, *20 or more on upper proepisternum; mesepimeron with a lower anterior line of setae; tarsi dark-scaled; all ungues of both sexes toothed, *larger midunguis of males with 2 teeth; remigium of wing with conspicuous setae; alula with extensive marginal fringe; tergum I largely bare, laterotergite with small scale-patch; *abdominal terga of males with numerous lateral setae. FEMALE GENITALIA – Segment VIII partially retracted; tergum VIII largely covered with setae; cercus short and broad. MALE GENITALIA – Segment VIII narrowed at base; tergum IX long, poorly sclerotised, lobes small, with setae; sternum IX well developed, with median patch of setae; gonocoxite elongate, simple, mesal membrane from base to apex; claspette short, rounded, bearing numerous specialised setae; gonostylus long, slender, widened in basal 0.6; gonostylar claw apical, slender; aedeagus simple; ventral paramere long; proctiger strongly developed, basolateral sclerotisation long; tergal area with 2 membranous lobes; paraproct with strong apical tooth; cercal setae present. EGGS – *Greatly expanded, more or less diamond-shaped in lateral outline. LARVAE – Head broad; seta 4-C between level of setae 5 and 6; setae 12,13-C approximated; antenna short, simple, without spicules, seta 1-A inserted near mid-length; seta 13-P absent; seta 5-M poorly developed; *seta 7-M as long as seta 5-M; setae 9–12-T removed cephalad and dorsad close to mesonotal setae; seta 6-I–V strongly developed, branched, seta 6-VI short, multi-branched; seta 7-I strongly developed; seta 12-I present; seta 2-III–VI near seta 1, seta 2-VIII larger than seta l-VIII; seta 4-VIII multi-branched, inserted near seta 3; comb of small fringed scales in large patch; siphon rather swollen, acus absent; pecten spines closely spaced except those at base; seta 1-S large, multi-branched; lobes of spiracular apparatus small; trachea strongly swollen; saddle incomplete, very small, acus absent; seta 1-X small, not inserted on saddle; seta 2-X multi-branched; seta 3-X single; ventral brush (seta 4-X) with 7 pairs of setae on grid; anal papillae represented by slight lobes. PUPAE – Trumpet short, broad, tracheoid developed at base; seta 8-CT caudad to level of trumpet; setae 2,3-I approximated; seta l-II short, removed from caudal margin, seta l-III–VII short; *seta 2-II as long as seta 1-II, seta 2-III–V only slightly mesad of seta 1, seta 2-VI,VII laterad of seta 1; *seta 3-I longer than seta 6-I; *seta 5-II longer than seta 3-II; seta 9-VI small, similar to 9-II–V, slightly dorsal; segment VIII very short, seta 4-VIII removed mesad; genital lobe of females only slightly projecting; paddle very large, wider than segment VIII; margins without distinct spicules. See Aedes.
The male genitalia of species of subgenus Halaedes have a generalised but distinct small claspette that is only found elsewhere in some species of subgenus Aedimorphus. The immature stages share several features with species of genus Opifex. Halaedes was recovered in a clade comprising Acartomyia + (Jarnellius + (Halaedes + Opifex)) in a sister-group relationship with subgenus Ochlerotatus in the phylogenetic study of Reinert et al. (2009). Cook et al. (2005) investigated the relationships among 20 species of six subgenera of Aedini – Halaedes (3), Aedes (1), Aedimorphus (1), Diceromyia (2), Ochlerotatus (10) and Stegomyia (3) – based on sequences for the cytochrome oxidase c subunits I and II (COI, COII) of mitochondrial DNA. The three species of Halaedes formed a strongly supported clade in the COII phylogeny (bootstrap value = 99, COI sequence was not available for these species) comprised of Ae. ashworthi + (Ae. wardangensis + Ae. australis). Brust & Mahon (1997) surmised that the anautogenous Ae. ashworthi in Western Australia may have diverged from Ae. australis in eastern Australia. Belkin (1962) believed that Halaedes is a relict taxon with its species preserved in a highly specialised habitat. Halaedes was recovered as the sister of genus Opifex, and this pair was sister to Acartomyia, in the phylogeny of Wilkerson et al. (2015). In the maximum likelihood phylogeny of Soghigian et al. (2017) based on seven molecular markers, species of Halaedes comprised a distinct lineage within a clade that included species of Geoskusea, Kenknightia, Ochlerotatus and Phagomyia.
Females of Ae. ashworthi and Ae. wardangensis are anautogenous whereas those of Ae. australis are generally autogenous in the first ovarian cycle (Brust, 1997). The immature stages are found in saline rock pools located at or slightly above the high-tide mark along rocky coastlines.
Aedes australis is known to feed on humans and is a reported pest in eastern Tasmania. Females of this species from Tasmania and New Zealand have been infected experimentally with Ross River virus, and the New Zealand population is capable of transmitting the virus (see references in Brust, 1997).
Southern part of the Australasian Region, including Lord Howe and Norfolk Islands in the South Pacific.
Belkin, 1962 (taxonomy/systematics); Lee et al., 1984 (taxonomy/systematics); Reinert et al., 2004, 2008, 2009 (as genus, morphology, phylogeny); Wilkerson et al., 2015 (phylogeny, classification); Soghigian et al., 2017 (phylogenetic relationships).