Tribe Sabethini Blanchard, 1905
Sabethes Robineau-Desvoidy, 1827. [The subfamily name Sabethinae was established by Blanchard (1905) (as Sabettinae, which has priority over Sabethinae Dyar, 1906). In accordance with the Principle of Coordination (International Commission on Zoological Nomenclature, 1999: Article 36.1), Blanchard (1905) is considered to have simultaneously established the coordinate tribal name Sabethini.]
Subfamily Culicinae. Tribe Sabethini includes 440 currently recognised species that comprise 14 genera (number of species in parenthesis): Isostomyia (4), Johnbelkinia (3), Kimia (5), Limatus (9), Malaya (12), Maorigoeldia (1), Onirion (7), Runchomyia (8), Sabethes (42), Shannoniana (4), Topomyia (68), Trichoprosopon (14), Tripteroides (123) ; Wyeomyia (140). Species of the tribe are referred to as 'sabethines'.
Sabethine adults are difficult to characterise. Most species have the base of the hindcoxa in line with or slightly above the base of the mesomeron, the mesomeron is generally distinctly smaller than in non-sabethine mosquitoes, prespiracular setae or scales are virtually always present (absent in one species of Malaya; scales replace setae in Limatus) and the mesopostnotum usually has a cluster of setae or scales. The position of the hindcoxa relative to the mesomeron is not universal among sabethines and is not unique to the tribe. It is below the base of the mesomeron in Maorigoeldia, some Malaya, and some Tripteroides, and many species of tribe Aedini, including Armigeres, Udaya, Zeugnomyia and certain Aedes and Heizmannia, resemble the majority of sabethines in having the base of the hindcoxa in line with the base of the mesomeron. Of the culicine genera, prespiracular setae are found elsewhere only in species of Culiseta and Psorophora, but these species are easily distinguished from sabethines based on other characteristics. Mesopostnotal setae are absent in Kimia, Malaya, Maorigoeldia, Topomyia and some Tripteroides, and are present in many species of the tribes Aedini and Culicini. The reduction of the larval ventral brush (seta 4-X) to one or rarely two pairs of setae is more or less diagnostic for the tribe (the homology of these setae with the ventral brush of non-sabethines is questionable). The position of seta 3-C on the ventral side of the head and the lateral displacement of the anterior labropalatal setae (seta 3a-Lp, see seta 3-Lp) appear to be diagnostic of sabethine larvae, but these characters are not always easy to see.
The following descriptions of principal taxonomic features (excluding those above) are provided to illustrate the varied development of the tribe. ADULTS - Eyes contiguous or narrowly separated above antennae; erect scales of head restricted to a single posterior row or absent; clypeus sometimes with setae or scales; proboscis variable in length and development; antennae shorter than proboscis; scutal scales varied, setae reduced or absent; mesopostnotum with setae or scales or both, sometimes bare; paratergite bare; antepronota often large and close together; postpronotum with or without posterior setae; postspiracular setae absent; prealar setae few or absent; lower mesepimeral setae absent; hindtibia markedly shorter than hindtarsomere 1; tarsi normal, pulvilli not evident; wing membrane with distinct microtrichia; cell R2 longer than vein R2+3; vein Rs often with basal line of scales; vein 1A usually ending distal to base of mediocubital crossvein (not so in Malaya and some Topomyia); subcosta without setae at base ventrally; upper calypter varied, with or without setae or hair-like scales, laterotergite varied, with complete or partial covering of scales or bare; tip of abdomen blunt in females. LARVAE - Occipital foramen circular with distinct collar or transverse and slit-like without collar; hypostomal suture complete, incomplete or absent; maxillae or mandibles often developed for grasping, maxillary brush unmodified or represented by a maxillary bundle or maxillary claw for grasping; seta 2-C absent; seta 13-P usually absent (present in Maorigoeldia, Tripteroides and a few Wyeomyia); no plumose or palmate setae on thorax or [/no-lexicon]abdomen[/no-lexicon]; seta 12-I absent; comb rarely absent; seta 5-VIII usually inserted near or above dorsal margin of segment X; siphon with at least one pair of setae, usually more, in addition to setae 1,2-S; pecten developed as spines, filaments or absent; saddle incomplete. See Culicinae.
The cladistic analyses of Judd (1996), Harbach & Kitching (1998) and Harbach & Peyton (2000) confirmed the monophyly of tribe Sabethini and indicated that the Old World genera comprise a paraphyletic assemblage relative to the monophyletic New World taxa. Contrary to these findings, the New World genera of Sabethini were not recovered as a monophyletic clade in a derived relationship to the Old World genera when Harbach et al. (2007) included the new genus Kimia in the cladistic analysis of Harbach & Peyton (2000). The New World genus Trichoprosopon was paired with the Old World Tripteroides in a sister relationship with Kimia, and the Old World Malaya, which was sister to Topomyia in the previous analyses, was placed as sister to the New World Limatus.
Sabethine larvae are almost entirely restricted to water contained in dead and living plant material, including leaf axils, bromeliads, bamboo, tree-holes, flower bracts and spathes, and pitcher plants. A few species have been collected from snail shells and rock holes, and several are capable of developing in artificial containers. Some species require a specific host plant. Predacious larvae are known in several genera. The mandibles or maxillae of these species are modified for capturing prey. Most if not all sabethine larvae lie on their backs at the bottom of the cavity and seldom come to the surface. Sabethine adults are forest mosquitoes. The females of most species suck blood and sometimes bite humans. Many species are active during the day. The majority of species fly with the hindlegs bent upward and over the back.
Sabethines as a whole are not important as vectors of disease agents. Various species of Limatus, Sabethes, Johnbelkinia, Trichoprosopon and Wyeomyia have been implicated in the transmission of arboviruses in the Neotropical Region, but none of the Old World species are even suspected of transmitting pathogens to humans or other animals.
Species of Sabethini are found mainly in the Neotropical, Oriental and Australasian Regions. Only a few species occur in temperate regions. Nine genera are almost entirely restricted to the Neotropical Region. These include Isostomyia, Johnbelkinia, Limatus, Onirion, Sabethes, Shannoniana, Runchomyia, Trichoprosopon and Wyeomyia. A few species of Wyeomyia occur in eastern North America. Only five genera are recognised in the Old World. Genus Malaya occurs in Africa as well as the Oriental and Australasian Regions, Topomyia is known from the Oriental Region and New Guinea, Maorigoeldia is restricted to New Zealand, Kimia occurs in eastern areas of the Oriental Region, and Tripteroides occurs in the Oriental, Australasian and the southern part of the Palaearctic.
Belkin, 1962 (South Pacific, systematics, bionomics, distribution); Lane, 1953 (Neotropical Region); Forattini, 1965 (Neotropical Region); Belkin et al., 1970 (New World); Tanaka et al., 1979 (Japan, taxonomy); Harbach & Peyton, 1993 (larval mouthparts); Judd, 1996 (phylogeny); Harbach & Peyton, 2000 (phylogeny); Harbach et al., 2007a (phylogeny).