Aedes

Azari-Hamidian, Shahyad & Harbach, Ralf E., 2009, Keys to the adult females and fourth-instar larvae of the mosquitoes of Iran (Diptera: Culicidae), Zootaxa 2078, pp. 1-33 : 20-21

Key to subgenera, species, and subspecies of genera Aedes and Ochlerotatus : fourth-instar larvae

(larva of Oc. chelli is unknown) (key characters are illustrated in Figs 5 and 6 )

1. Siphon without acus (auricle) (with indistinct acus in Ae. vittatus ) [antenna smooth or very sparsely spiculate; seta 1-A (antennal tuft) with at most 4 branches; seta 12-I absent] ................................................................................ 2

- Siphon with well-developed acus.............................................................................................................................4

2(1). Pecten with 1, sometimes 2, apical spines distinctly separated from other spines beyond seta 1-S (siphonal tuft); seta 1-A (antennal tuft) with 2 or 3 branches, inserted slightly before middle of shaft; seta 4-X (ventral brush) with 2 or more precratal setae; seta 4-C (postclypeal seta) and 6-C (median frontal seta) on level with base of antenna; seta 4-C minute, with very few (2–4) fine branches; seta 5-II–V single, rarely double; antenna very sparsely spiculate; anal papillae (gills) wider at base and pointed apically, more than 2.0 length of saddle [SI 2.0 (1.9–3.1); seta 7-C usually with 2 or more branches, rarely single; comb scales with apical spine, without subapical spines; PTF 1:1:2:1:1:1:2–3] ( Aedes subgenus Fredwardsius ) ................................................................................... Ae. vittatus

- Pecten with spines equally spaced, sometimes 1 or 2 apical spines slightly more widely separated but not distinctly and not beyond seta 1-S; seta 1-A single, inserted slightly beyond middle of shaft; seta 4-X without precratal setae; setae 4,6-C inserted far forward on head; seta 4-C well developed, usually with 5 (4–7) branches; seta 5-II–V branched; antenna smooth; anal papillae sausage-shaped with round ends, 2.5–3.0 length of saddle ( Aedes subgenus Stegomyia )................................................................................................................................................. 3

3(2). Comb scales with stout subapical spines; basal tubercle(s) of setae 9–12-M,T (meso- and metapleural groups of setae) strongly sclerotized, curved and pointed, spine-like; seta 4-X (ventral brush) with 5 pairs of setae, each usually two-branched (2 or 3); seta 7-C (outer frontal seta) single, rarely double [SI 1.5–2.5; PTF 2–3:1:2:1–2:2:1:2–3] ............................................................................................................. Ae. aegypti * (Note 24)

- Comb scales without subapical spines; basal tubercle(s) of setae 9–12-M,T with only small denticles; seta 4-X with 4 pairs of setae, each single; seta 7-C usually with 2 or more branches, rarely single [SI 2.0; PTF 3–4:1:2:2–3:1–2:1:2–3] .................................................................................................................... Ae. albopictus *

4(1). Pecten with 1, sometimes 2, apical spines distinctly separated from other spines, more curved and stouter than others and usually without secondary denticles; seta 1-S (siphonal tufts) small, length about 0.5 width of siphon at point of attachment; seta 12-I absent [antenna spiculate; seta 1-A (antennal tuft) with 5-12 branches; 9–12 comb scales arranged in single or double row; SI 3.0–3.5 (2.1–4.3); lateral palatal brush (LPB) (labral brush) with distally dentate filaments; PTF 1:1:1–3:1–2:1:1:2–3] ( Aedes subgenus Aedimorphus ) .............. Ae. vexans (Note 25)

- Pecten with spines regularly or irregularly spaced but without apical curved and stout distinctly separated spines; seta 1-S large, length more than 0.5 width of siphon at point of attachment, except Oc. caballus ; seta 12-I present (genus Ochlerotatus ) (Note 4) .................................................................................................................................. 5

5(4). Thorax and abdomen with stellate setae; antenna smooth, without spicules; pecten spines long, pointed, equally spaced [seta 1-A (antennal tuft) single; comb scales in a single row; tree-hole larva] ( Ochlerotatus subgenus Finlaya ) ......................................................................................................................................................................... 6

- Thorax and abdomen without stellate setae; antenna spiculate even if only sparsely; pecten spines short, not spine-like, with a broad base ( Ochlerotatus subgenus Ochlerotatus ) ...................................................................... 7

6(5). Pecten about 0.5 length of siphon, usually with 18–22 (15–27) spines; setae 1,2,5-I (stellate setae of abdominal segment I) obviously longer than segment, some with 5-10 branches; seta 6-III–VI (lateral seta on abdominal segments III–VI) long and stout; dorsal pair of anal papillae (gills) about 2.0 length of ventral pair and distinctly longer than saddle [SI 3.0–3.5; PTF 3–5:1:5–8:6-8:2:1:2] .......................................................................... Oc. echinus

- Pecten distinctly less than 0.5 length of siphon, usually with 15 (14–20) spines; setae 1,2,5-I about as long as segment, at most 6-branched; setae 6-III–VI shorter and more slender; dorsal pair of anal papillae about 1.5 length ventral pair and slightly longer than saddle [SI 2.0–3.0; PTF 3–4:1:3-6:4–7:2:1:2] ....... Oc. geniculatus (Note 26)

7(5). Antenna sparsely spiculate; anal papillae (gills) very long at least 2.0 length of saddle, sausage-shaped with round ends; seta 1-X (saddle seta) at least 2.0 length of saddle; head about as broad as long; median filaments of lateral palatal brush (LPB) (labral brush) not apically serrate; seta 1-S (siphonal tuft) at least 2.0 width of siphon at point of attachment, inserted well below middle of siphon [seta 1-A (antennal tuft) with 2–4 branches; tree-hole larva] ( Pulcritarsis Complex) (Note 29).............................................................................................................................. 8

- Antenna well spiculate; anal papillae less than 2.0 length of saddle; seta 1-X less than 2.0 length of saddle; head broader than long; median filaments of LPB apically serrate; seta 1-S less than 2.0 width of siphon at point of attachment, inserted on or beyond middle of siphon (may be slightly below middle in Oc. dorsalis and Oc. leucomelas ) .................................................................................................................................................................. 10

8(7). Seta 1-S (siphonal tuft) at about 0.5 length of siphon, less than 2.0 width of siphon at point of attachment; comb with 6–11 scales in a single row; siphon index (SI) usually under 5.0 (3.0–5.2); anal papillae (gills) equally long; seta 1-A (antennal seta) inserted on or slightly beyond middle of shaft [PTF 3:1–2:2–4:3–4:3–4:1:5] Oc. pulcritarsis ......................................................................................................................................................................... 9

- Seta 1-S at about 0.33 length of siphon, more than 2.0 width of siphon at point of attachment; comb scales usually more numerous (16–20), often arranged in an irregular triangular patch; SI usually more than 5.0 (3.5–7.8); dorsal pair of anal papillae longer than ventral pair; seta 1-A inserted well beyond middle of shaft [PTF 2–3:1:2:2–3:2- 3:1:3–4] .............................................................................................................................................. Oc. berlandi *

9(8). Siphon index (SI) 4.0–5.0; siphon slightly but uniformly tapered toward apex; anal papillae (gills) usually as long as siphon ..................................................................................................................... Oc. pulcritarsis pulcritarsis

- SI 3.0–3.5; siphon strongly tapered toward apex; anal papillae usually twice as long as siphon .............................. ........................................................................................................................................... Oc. pulcritarsis asiaticus

10(7). Seta 4-X (ventral brush) with 4–7 precratal setae (arising anterior to grid); seta 1-X (saddle seta) about 1.3 length of saddle; siphon index (SI) greater than 3.0 (3.2–4.0) [PTF 1:1:2–3:1:2:1:3–8] ............................. Oc. flavescens

- Seta 4-X with at most 3 precratal setae; seta 1-X shorter than 1.3 length of saddle, usually at most as long as saddle; SI usually not more than 3.0 ........................................................................................................................... 11

11(10).Seta 1-A (antennal tuft) single or double; comb with about 10 large scales with secondary denticles confined to base; anal papillae (gills) about 1.5 length of saddle; length of seta 1-S (siphonal tuft) at most 0.5 width of siphon at point of attachment [SI 2.6–2.9; seta 1-X (saddle seta) about half as long as saddle; PTF 1:1:1-4:1:1:1-2:3 ....... .............................................................................................................................................. Oc. caballus (Note 28)

- Seta 1-A with more than 3 branches; comb with more than 10 (usually more than 20) scales or spines; anal papillae no longer than saddle, usually shorter; seta 1-S more than 0.5 width of siphon at point of attachment........... 12

12(11).Comb with more than 25 (usually more than 35) scales, scales without main spine; anal papillae (gills) spherical and very short; setae 2–6-P (prothoracic setae 2–6) usually single; seta 5-C (inner frontal seta) with 2–5 branches; seta 6-C (median frontal seta) usually with 2 or 3 branches, rarely single [SI 3.0 (1.8–3.5); seta 1-X (saddle seta) nearly as long as saddle; PTF 2:1:1:1:1:1:3] ......................................................................................... Oc. detritus

- Comb with fewer than 25 scales, at least some scales with long main spine; anal papillae not spherical; at least one of setae 2–6-P branched; seta 5-C usually single, rarely with 2 branches; seta 6-C usually single, rarely with 2 or 3 branches .......................................................................................................................................................... 13

13(12).Seta 4-X (ventral brush) with long main basal stem, at least 1.5–2.0 length of transverse grid bar at base of central cratal seta; anal papillae (gills) tapering; seta 1-X (saddle seta) nearly as long as saddle [SI 2.6 (2.2–4.2); PTF 1–2:1:1:1:2:1:3] ............................................................................................................................... Oc. leucomelas

- Seta 4-X branched from near base, main stem subequal to length of transverse grid bar at base of central cratal seta; anal papillae rounded; seta 1-X short, about 0.5 length of saddle ( Caspius Complex) (Note 30) ................. 14

14(13).Seta 1-S (siphonal tuft) inserted beyond middle of siphon, usually with more than 5 (5–10) branches; seta 1- III–VI short with more than 2 simple branches; seta 3-VIII usually with more than 8 branches; seta 1-P (prothoracic seta 1) usually single [SI 2.9 (1.4–3.2); PTF 1:1:2:1:1–2:1:3] ................................................ Oc. caspius s.l.

- Seta 1-S inserted about midlength of siphon, usually with fewer than 5 (3-6) branches; seta 1-III–VI long with 2 aciculate branches; seta 3-VIII usually with fewer than 8 branches; seta 1-P usually double [SI 2.3 (1.4–3.0); PTF 2:1:2:1:2:1:3] ...................................................................................................................................... Oc. dorsalis *

Figures

FIGURE 5. Characters of the head of mosquito larvae used in the keys. Dorsal and ventral aspects of a culicine larva. (Modified from Harbach & Knight, 1980).

FIGURE 6. Characters of mosquito larvae used in the keys. A, Lateral aspect (right side) of an aedine larva. B, C, Lateral aspects (left sides) of the terminal abdominal segments of a Culiseta and an Anopheles larva, respectively. (Modified from Harbach & Knight, 1980).