Subgenus Rusticoidus Shevchenko & Prudkina, 1973

Type species: 

Aedes refiki Medschid, 1928.

Classification: 

Subfamily Culicinae, genus Aedes. Subgenus Rusticoidus includes nine species, one consisting of two subspecies.

Characteristics: 

The species and subspecies of subgenus Rusticoidus are distinguished from other species of genus Aedes and other Aedini in the Holarctic Region by the following combinations of characters. Characters that diagnose subgenus Rusticoidus in the phylogenetic analyses of Reinert et al. (2009), based on Ae. refiki and Ae. rusticus, are indicated by an asterisk (*).

ADULTS – Large mosquitoes; *ocular line of head broad; antennal pedicel of females with large mesal and *lateral scale-patches (patches sometimes contiguous dorsally); parascutellar area with 1-6 scales and 1-3 setae; scutum and scutellum with narrow scales only; *anterior acrostichal and *posterior acrostichal areas with pale-scaled stripe; membrane posteromesad of metapostnotum with patch of broad scales; *antepronotum with both narrow and broad scales; *postpronotum with only broad decumbent scales; antepronotum, upper proepisternum and prealar area with large number of long setae; *lower proepisternal scales present; hypostigmal area with broad scales; subspiracular area with elongate patch of broad scales; mesepimeron with 1-8 long setae on anteroventral area; metameron with broad scales; remigium of wing with dorsal setae inserted proximally; *ante- and postprocoxal scales present; *hindtarsomere 2 without basal pale scales; ungues of males each toothed, larger fore- and midungues with 2 teeth. FEMALE GENITALIA – Tergum VIII and sternum VIII largely covered with broad spatulate scales (except in Ae. bicristatus), *posterior margin of sternum with median emargination separating broadly rounded lateral lobes; dorsal surface of cercus with broad spatulate scales on distal 0.6, ventral surface with several setae on distal 0.5–0.6 and few broad spatulate scales; postgenital lobe with median apical indentation, ventral surface narrowly connected with upper vaginal lip; upper and lower vaginal sclerites absent; insula lip-like, with 2–4 setae on either side of mid-line; 3 spermathecal capsules. MALE GENITALIA – Ninth tergal lobes with stout flattened setae; sternum IX with heavily pigmented round median caudal area with setae and similar lateral triangular strips; gonocoxite with basal dorsomesal lobe bearing specialised setae; claspette moderately thick with short annulated filament; aedeagus simple, long and narrow, narrowest in middle, base with circular opening (bearing lateral triangular flaps in some species), apex with small median lobe separating lateral flattened areas bearing minute spicules; paraproct heavily pigmented, with curved pointed apex. LARVAE – Antenna spiculate, seta 1-A short, branched; *seta 1-C single, thin, attenuate distally; seta 4-C branched, inserted slightly posterior to seta 7-C and anteromesal to seta 6-C; seta 5-C inserted caudomesad of seta 6-C, slightly lateral to seta 4-C; *seta 4-P about as long as seta 3-P; *seta 8-P ≥ 1.8 length of seta 4-P; seta 12-P very long, single; *seta 1-M ≥ 3 branches; seta 12-I present, short; *seta 3-VII 0.48−0.85 mid-dorsal length of segment X; seta 1-VIII noticeably shorter than setae 3,5-VIII, *0.50–0.95 length of seta 2-VIII; comb scales spine-like, borne in 1 or 2 irregular rows; siphon with an accessory seta 1-S inserted on anterior side of pecten proximal to level of usual seta 1-S (*≥ 2 setae 1-S) and 1–4 accessory anterolateral seta 2a-S; seta 9-S stout, hook-like; pecten with 1 or more distal spines more widely spaced; saddle incomplete ventrally, without acus; ventral brush (seta 4-X) with 2–6 precratal setae and posterior setae on grid with lateral and transverse bars. PUPAE (only known for Ae. quasirusticus and Ae. rusticus) – Seta 11-CT inserted closer to seta 10-CT than to seta 12-CT; seta 2-II,VII inserted lateral to seta 1, seta 2-III–VI inserted mesad of seta 1; seta 5-IV–VI very long; paddle noticeably longer than wide; seta 1-Pa usually single, occasionally forked or branched; seta 2-Pa absent. See genus Aedes.

Phylogenetic relationships: 

Within the phylogeny of Aedini generated in the study of Reinert et al. (2009) based on extensive morphological data, subgenus Rusticoidus was recovered as the sister of Ae. flavescens in a clade of a large number of species that is diagnosed by the unique presence of parascutellar scales.

Bionomics and disease relations: 

The species of subgenus Rusticoidus are monocyclic snow-melt mosquitoes that over-winter in the egg stage. Some larvae hatch in late autumn and pass winter in the larval stage, others hatch early the following year during or shortly after snow-melt, or after heavy rainfall. Larvae are predominantly found in semi-permanent and permanent collections of water in woodlands, primarily swampy and marshy habitats, but are also found in ditches and flooded meadows. Adults are usually encountered close to larval habitats, emerging from late April to June. The females are mainly zoophilic but several species, including Ae. refiki, Ae. rusticus, Ae. subdiversus and Ae. bicristatus, are known bite on humans at dusk and during the day in shaded situations.

Species of subgenus Rusticoidus are not known to be of medical or economic importance to humans.

Distribution: 

Species of subgenus Rusticoidus have distributions in the Holarctic Region. Seven species occur in the Palaearctic, principally in Europe, and two occur in the Nearctic. Aedes albescens and Ae. krymmontanus are only known from Russia and the Ukraine, respectively. Aedes lepidonotus is recorded from southeastern Europe and Ae. quasirusticus is only recorded from Spain. Aedes rusticus and Ae. refiki are widely distributed in Europe and are found in Asia Minor, and the former also occurs in areas of northern Africa. Aedes subdiversus is known from the European part of Russia to Kazakhstan and southern Siberia. Aedes bicristatus is known only from California and Ae. provocans occurs in North America, from the Northwest Territories and British Columbia to Nova Scotia in Canada and from Washington State to Georgia in the USA.

Principal references: 

Carpenter & LaCasse, 1955; Wood et al., 1979 (Ae. bicristatus and Ae. provocans, respectively, description, biology, distribution); Reinert, 1999 (taxonomy, morphology); Reinert, 2002 (as subgenus of genus Ochlerotatus, female genitalia); Alcíbar, 2004, 2005 (pupa of Ae. quasirusticus and Ae. rusticus, respectively); Reinert et al., 2004, 2006, 2008, 2009 (as subgenus of genus Ochlerotatus, morphology, phylogeny); Becker et al., 2010 (as subgenus of genus Ochlerotatus, descriptions, biology, distributions); Wilkerson et al., 2015 (status as species group); Wilkerson & Linton, 2015 (status as subgenus of Aedes).

Species: 

albescens Edwards, 1921
bicristatus Thurman & Winkler, 1950
krymmontanus Alekseev, 1989
lepidonotus (Edwards, 1920)
provocans (Walker, 1848)
quasirusticus Torres Cañamares, 1951
refiki Medschid, 1928
rusticus (Rossi, 1790)
     subspecies rusticus (Rossi, 1790)
     subspecies subtrichurus Martini, 1927
subdiversus Martini, 1926

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