Ochlerotatus (Woodius), 2009

John F. Reinert, Ralph E. Harbach & Ian J. Kitching, 2009, Phylogeny and classification of tribe Aedini (Diptera: Culicidae), Zoological Journal of the Linnean Society 157, pp. 700-794 : 775-777

OCHLEROTATUS SUBGENUS WOODIUS REINERT, HARBACH AND KITCHING , SUBGEN. NOV.

Type species: Aedes intrudens Dyar, 1919 .

Females

Head: Vertex covered with narrow, curved, decumbent scales; occiput and vertex with numerous, long, pale, erect, forked scales; ocular line with narrow, curved, pale scales; eyes above antennal pedicels separated by diameter of 3 or 4 ocular facets; antennal pedicel with few small, broad, non-overlapping scales and several short, slender setae on mesal surface; clypeus bare; maxillary palpus dark-scaled (occasionally with few pale scales intermixed in Oc. intrudens ); proboscis dark-scaled, longer than forefemur.

Thorax: Scutum covered with narrow, curved scales except bare median, prescutellar area, both pale and dark scales present, pale scales covering scutal fossal, antealar, much of supraalar, usually narrow stripe on acrostichal (anterior and posterior) and lateral margins of prescutellar areas; without parascutellar scales; scutellum with narrow, curved scales on all lobes; acrostichal (anterior and posterior), dorsocentral (anterior and posterior) and prescutellar areas with numerous setae; antepronota widely separated, with pale scales, several setae; postpronotum nearly covered with scales, narrow, curved on dorsal area and moderately broad to broad on ventral area, several posterior setae; postspiracular area with broad, pale scales, several setae; subspiracular area with elongate patch of broad, pale scales; upper proepisternum with broad, pale scales, numerous setae, lower proepisternum bare; prealar area with patch of broad, pale scales on lower area and extending onto lower part of upper area, numerous setae; mesokatepisternum with broad, pale scales in large upper and moderate lower posterior patches, patches connected or separated by narrow strip, several upper and numerous lower posterior setae; mesepimeron with large patch of broad, pale scales on upper and extending over middle areas, numerous upper setae, lower setae absent in Oc. diantaeus or absent to 1–4 setae in Oc. intrudens ; metameron with several broad, pale scales.

Wing: Dark-scaled; upper calypter with numerous setae on margin; alula with dark scales on posterior margin; dorsal tertiary fringe scales dark; remigium with 1–3 setae distally on dorsal surface.

Legs: Ante- and postprocoxal membranes bare; femora with pale-scaled fringe at apex; tibiae with anterior surface dark-scaled; tarsi dark-scaled, ungues equal in size, each with 1 tooth.

Abdomen: Tergum I with patch of broad, pale scales on laterotergite; segment VII dorsoventrally flattened.

Genitalia: Intersegmental membrane between segments VII and VIII very long; tergum VIII moderately pigmented, width greater than length, without or with 1–7 scattered scales, short setae on approximately distal 0.90, apex flat to very gently concave; sternum VIII moderately pigmented, width greater than length, apical margin gently rounded or gently rounded with shallow, median emargination, moderate number of scales, setae on nearly entire area; tergum IX comprised of single moderately pigmented sclerite, apex with small, median emargination separating rounded lobes each bearing 4–9 short, slender setae, 9–17 total setae; postgenital lobe moderately wide, apex with small, median emargination, several setae on distal area; without upper and lower vaginal sclerites; insula lip-like, with 2 or 3 moderately long, slender setae in lateral patches, 4–6 total setae; cercus moderately pigmented, long, narrow, apex narrowly rounded, 1–3 scales, numerous setae extending from near base to apex of dorsal surface; 3 spermathecal capsules, spherical, 1 large and 2 slightly smaller.

Males

Head: Antenna with distal 2 flagellomeres disproportionally long, remainder of flagellomeres short with numerous long setae directed primarily dorsally and ventrally; maxillary palpus with 5 palpomeres, darkscaled, equal to or longer than proboscis, palpomeres 4 and 5 slightly downturned, palpomeres 4 and 5 and distal part of 3 with moderate to numerous long setae lateroventrally.

Legs: Fore- and midungues unequal, each with 1 tooth; hindungues equal, each with 1 tooth.

Abdomen: Terga with moderate to numerous long, slightly curved setae laterally.

Genitalia: Tergum IX moderately to heavily pigmented, posterior margin with darkly pigmented, short, relatively narrow lobe on each side of midline bearing 5–9 short, stout, slightly curved setae; gonocoxite moderately to heavily pigmented, relatively long, moderately wide, dorsal surface with several short, slender setae on mesal area, several moderately long, slender setae on distal area and long, stout setae on lateral area, mesal area with large, apical lobe bearing few short, slender setae, small, basal lobe bearing 1 moderately long, stout, somewhat flattened seta and few short, slender setae, lateral surface with several long, stout setae, ventral surface with several moderately long, slender setae on proximal area, distal area with few long, stout setae and patch of moderately long, lanceolate setae on mesal part, scales few on dorsal surface and numerous on lateral and ventral surfaces, mesal surface membranous; gonostylus attached at apex of gonocoxite, long, approximately 0.60–0.65 length of gonocoxite, relatively narrow throughout length but median part somewhat broader than proximal part, distal part curved mesally and narrower than proximal part, with 2–5 short, slender setae, gonostylar claw short, slender, apex truncate, attached at apex of gonostylus; aedeagus tube-like, moderately long, proximal 0.67 relatively wide, distal part relatively narrow; phallosome with basal piece short; proctiger moderately long, distal part darkly pigmented with curved, pointed apex, numerous minute, cercal setae; claspette comprised of 2 lobes, outer lobe moderately long, projecting along proximal part of mesal surface of gonocoxite and bearing 2 moderately long, darkly pigmented, moderately curved setae at apex, lobe connected at base to inner, moderately long, slender, columnar lobe with subapical area broader and bearing small, thumb-like projection with 1 short seta, claspette filament inserted at apex, short to moderately long, flattened, broad mesally; sternum IX moderately pigmented, moderately long, with several short to moderately long, slender setae on posterior area.

Pupae

Trumpet: Moderately long; relatively narrow distally; pinna short; tracheoid area weakly developed at base.

Cephalothorax: Setae 1,3-CT similarly developed, normally 2-branched; 4,5-CT similarly developed; 6-CT much shorter than 7-CT; 11-CT normally single (rarely 2-branched in Oc. intrudens ).

Abdomen: Seta 6-I longer than 3,7-I; 1-II short, with few to several slender branches; 3-II relatively short, single or 2-branched, shorter than 6-II; 3-III moderately long, normally single, longer than 5-III; 1-IV,V moderately long, slender, single or with 2–4 branches; 5-IV,V single to 3-branched, longer than median, dorsal length of following tergum; 6-VII shorter than and inserted posterior and slightly mesal to 9-VII; 9-VIII with 3–9 (normally 3–5) branches with distal parts forked.

Paddle: Apical margin rounded; without hair-like spicules on margins; midrib extends to near apex of paddle; seta 1-Pa short, single (very rarely 2-branched).

Fourth-instar larvae

Head: Seta 1-C spiniform, apex bluntly pointed; 4-C short, with 3–6 very slender branches, inserted mesal and at same level or slightly posterior to 6-C; 5-C long, stout, with 3 or 4 aciculate branches, inserted posteromesal to 6,7-C; 6-C long, stout, with 2–4 aciculate branches, inserted posteromesal to 7-C; 7-C long, stout, with 4–6 (rarely 3) aciculate branches; 12-C short, branched, inserted mesal to 13-C; 13-C single in Oc. intrudens or with 2 or 3 branches in Oc. diantaeus , longer than 12-C; 14-C single; 19-C present; antenna moderately long ( Oc. intrudens ) to long ( Oc. diantaeus ), with numerous spicules, seta 1-A with 3–5 aciculate branches, tips not reaching apex of antenna.

Thorax: Setae 1–3-P not inserted on common setal support plate, 1-P> 2-P> 3-P, 1-P very long, single, 2-P short, single, 3-P short, with 2 or 3 branches; 4-P single (rarely 2-branched); 5,6-P long, single, 5-P longer than 6-P; 7-P long, with 2 or 3 branches; 4-M and 2-T branched; 6-T single.

Abdomen: Setae 6-I–V and 7-I long, stout, single; 12-I present; 6-II slightly shorter than 6-III; 8-II normally 2-branched (occasionally single); 1-VII branched, relatively short; 10,12-VII single; 1-VIII with 5–8 branches, noticeably longer than 2-VIII; 2,4-VIII single (2-VIII rarely 2-branched in Oc. diantaeus ); comb with several scales in one curved or irregular row; segment X with saddle incomplete ventrally, acus present, seta 1-X single, inserted on saddle, 2-X moderately long, multiple-branched, 3-X long, single, ventral brush with numerous, long, branched setae inserted on grid with well developed transverse and lateral bars, with 3 or 4 shorter, branched, precratal setae.

Siphon: Moderately long; acus present; pecten with numerous spines, distal 2 or 3 spines longer and more widely spaced, seta 1-S inserted distal to pecten (rarely on level with last pecten spine in Oc. intrudens ).

Included species

Ochlerotatus diantaeus Howard, Dyar & Knab and Oc. intrudens.

Distribution

Nearctic and Palaearctic Regions.

Bionomics

Wood et al. (1979) reported that larvae of Oc. intrudens in Canada hatch from overwintering eggs in April and inhabit temporary, woodland, snowmelt pools. Carpenter & LaCasse (1955) indicated larvae of this species occur in a variety of habitats, including woodland pools, open bogs and marshes, particularly in water from melting snow in the northern United States, whereas Natvig (1948) found the larval habitats in Norway to be principally shallow pools and water-filled ditches with bottoms covered with decaying pine needles located at the border of pine woodlands, and Gutsevich et al. (1974) reported similar habitats in Russia. Larvae of Oc. diantaeus in Canada were found in temporary spring pools in hardwood forests in which the water was usually stained dark brown by abundant leaf litter ( Wood et al., 1979), in the United States larvae were found mostly in shaded pools with cold water left from melting snow in dense forests ( Carpenter & LaCasse, 1955), and in Russia Gutsevich et al. (1974) reported larval habitats as different types of temporary water bodies in forests formed from snowmelt, e.g. pits, ditches and puddles in shaded or open locations. Females of Oc. intrudens are persistent biters of humans during the day and night ( Carpenter & LaCasse, 1955; Wood et al., 1979). Ochlerotatus diantaeus females also feed on humans ( Gutsevich et al., 1974; Tanaka et al., 1979; Becker et al., 2003).

Discussion

Carpenter & LaCasse (1955), Wood et al. (1979) and Tanaka et al. (1979) included descriptions and illustrations of females, males, male genitalia and fourth-instar larvae of Oc. diantaeus and Oc. intrudens . Yamaguti & LaCasse (1951) and Reinert (2002e) provided a description and illustration of the female genitalia of Oc. intrudens and Darsie (1951) and Tanaka (1999) described and illustrated the pupa of this species. Kalpage & Brust (1968), Horsfall & Voorhees (1972) and Dahl (1997) described and illustrated the eggs of Oc. diantaeus and Oc. intrudens . Distribution maps for both species in Canada are found in Wood et al. (1979) and in the United States and Canada in Darsie & Ward (2005). Additional descriptive information is provided in Appendix 1 for species included in the analysis.

Etymology

Woodius if named in honour of Dr D. Monty Wood in recognition of his important contributions to the taxonomy of mosquitoes and other Diptera of North America, especially Canada. The subgeneric name is masculine, formed from his surname and the masculine Latin suffix ‘ -ius ’. Recommended subgeneric abbreviation = Woo.